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Microbiology Introduction & enterobacteriacae Ziad Al-Nasser Mohammad Abu 3assi Monday, 31/10/2011
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بسم اهلل الرحمن الرحيم Monday, October 31, 2011 First lecture of microbiology: Introduction & enterobacteriacae
Introduction In microbiology of GIT we are going to talk about most microorganisms that infect the GIT, especially those which cause diarrhea, and those which enter the GIT and end somewhere else. To do this, you should know the micro flora inhabiting the GIT. We will also talk about viruses, protozoa and helminthes that infect the GIT. Certain microorganisms use the gastrointestinal tract (the fecaloral route) as a vehicle to pass to the blood, then they could disseminate all over the body, especially to the reticuloendothelial system, causing septicemia, fever, diarrhea or sometimes even constipation. Typhoid fever and brucellosis are examples of these diseases that enter through the GIT and cause systemic diseases. The respiratory system is infected most commonly among all other systems of the body, followed by the GIT. Diarrhea and loss of fluid in general is the second cause of death in the world! When we talk about GIT infections, we focus mainly on food poisoning (oral-fecal route in particular), water contamination and gastroenteritis. Gastroenteritis is a common disease associated with diarrhea, nausea and vomiting. Some of the microbes that cause GIT infections secrete toxins; these toxins could be enterotoxins, cytotoxins or neurotoxins. Whenever you see some one with diarrhea, you have to ask yourself if this diarrhea is invasive or non-invasive. This is so important because when you 2
differentiate between the two types, you limit your choices for the causative microbe. Invasive diarrhea: caused by microbes that invade the GIT, in which you could see blood and WBC’s in stool (fecal leukocytes). Patients usually complain about tenesmus (urgent desire to evacuate the bowel or bladder, involuntary straining, and the passage of little fecal matter or urine). Those microbes include shigella, enteroinvasive Escherichia coli, salmonella enterica, salmonella enteritidis, campylobacter and some protozoa (entamoeba histolytica). Non-invasive diarrhea (watery diarrhea): there is no invasion to the GIT, the microorganism is just present in the lumen and its toxins are causing water and electrolytes to flow to the lumen. Those microbes include vibrio cholera, enterotoxigenic Escherichia coli, enteropathogenic Escherichia coli, cryptosporidium parvum and Giardia lamblia. Most of the diarrheas are self limiting. The early treatment is the supportive therapy (water and electrolytes replacement). The normal flora of the gastrointestinal tract is so important to defend us against pathogens. Antibiotics is the last choice to treat diarrhea, because by the use of antibiotics, we kill the normal flora leaving the stage open for the virulent microbes that could act as pathogens exaggerating diarrhea or causing pseudomembranous enterocolitis. Another reason to avoid or at least postpone the treatment with antibiotics, is that diarrhea might be associated with other causations, like chemicals, drugs, viruses (especially in children) or stress (irritable bowel syndrome )القولون العصبي The doctor read the following long table about food poisoning with some extra notes (written at the end of the table), so do what you want to with it (skip, read, memorize or analyze it)
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Types of foods associated with various pathogens that cause food poisoning. TYPES OF FOODS ASSOCIATED WITH VARIOUS PATHOGENS THAT CAUSE FOOD POISONING Pathogen Staphylococcus aureus
Foods Cream pastries, salads, meat products, cold foods
Bacillus cereus
Fried rice, vegetables, meat dishes, vanilla sauce
Clostridium perfringens
Cooked meats, gravies
Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus Campylobacter jejuni
Shellfish, seafood
Salmonella enteritidis
Eggs, poultry, other meats
Shigella spp.
Salads, milk, cold foods
Yersinia enterocolitica
Milk, pork products
Escherichia coli
Ground beef, milk, lettuce, unpasteurized cider
Listeria monocytogenes
Soft cheese, patĂŠ, milk, coleslaw
Clostridium botulinum
Meats, home-canned fruit and vegetables
Hepatitis A and enteric viruses
Shellfish, various foods
Milk, poultry
Staphylococcus aureus: common in food poisoning, favors sweet food, produce enterotoxins (the cause of diarrhea), extreme age groups are most vulnerable. Bacillus cereus: lab contaminant, affects immunocompromised, causes keratitis, common in Southeast Asia (fried rice) and in our area (MANASEF). Clostridium perfringens: favors meat. Vibrios: favor seafood (they live in salty water) or alkaline food (pH 8.5 – 9)
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Campylobacter jejuni: prefer GIT of birds, so could contaminate the cutting board after cutting a chicken for instance, then contaminating the salad if it is made on the same cutting board! Salmonella enteritidis: most common in food poisoning. Shigella: transmitted through fecal-oral route. Escherichia coli: many species, enterohemorrhagic Escherichia coli (the one that caused hemolytic uremic syndrome a few months ago in Denmark, Germany and Europe in general, through contaminating cucumbers) So, the most common microbes in contaminating food: Salmonella > Shigella > Campylobacter > Yersinia > E. coli > others As we said, you have to know the micro-organisms of the normal flora. If you examined a stool sample and saw klebsiella pneumoniae or proteus for example, you should know that they are part of the normal flora, so this normal. But the abnormal is to see them in a urine sample, because these micro-organisms could cause urinary tract infections (UTI)
Here is another long table but this is about water-borne infections, but here the doctor didn’t say any extra piece of information, he just read it.
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Micro-organisms associated with water-borne infections. MICRO-ORGANISMS ASSOCIATED WITH WATER-BORNE INFECTIONS Bact Vibrio cholerae eria
Virus es
Norwalk virus Small round-structured viruses Hepatitis A virus Prot
ozoa
Vibrio parahaemolyticus Campylobacter jejuni Shigella spp. Escherichia coli (especially enterotoxigenic Escherichia coli) Rotavirus
Hepatitis E virus Giardia lamblia Entamoeba histolytica Cryptosporidium parvum Isospora belli Cyclospora cayetanensis Microsporidia spp. Dientamoeba fragilis Balantidium coli
99% of bacteria that cause diarrhea are gram negative; most of these belong to the family of “Enterobacteriacae�. There are some gram positive bacteria that cause diarrhea like clostridium (gram positive bacillus, spore forming). So now we are going to talk about enterobacteriacae.
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Enterobacteriacae Enterobacteriacae is a large family of bacteria including salmonella, shigella, E. coli, yersinia and others, Gram negative rods. Oxidase negative, glucose fermenters, some ferment lactose (E.coli), others do not (salmonella, shigella, yersinia) and they utilize nitrates. They express O, H and K antigens. O antigen: somatic antigen, it is an oligosaccharide. H antigen: flagellar antigen. K antigen: capsular antigen. Deferent serotypes of enterobacteriacae are classified according to these antigens (especially O and H), for example O157 H7. They produce toxins (enterotoxins) and some produce cytotoxins. Most enterotoxins are heat labile and some are heat stable. Heat labile enterotoxins act as cholera toxin, which initiates ADP ribosylation in the lumen of GIT. ADP ribosylation activates adenylate cyclase enzyme, which converts ATP to cAMP, causing an increase in the level of cAMP in the lumen, so water and electrolytes will flow from the cells to the lumen causing diarrhea. Heat stable toxins work almost the same, but here by converting GTP to cGMP Enterobacteriacae as well as other micro-organisms of the normal flora could cause opportunistic infections in the lungs, wounds but the most common is the UTI. The most common micro-organism that causes UTI is E. coli (Opportunistic infections). Some cause dysentery (A disease marked by frequent watery stools, often with blood and mucus, and characterized clinically by pain, tenesmus, fever, and dehydration), which is fecal leukocyte positive with tenesmus. The most common micro-organisms that cause dysentery are shigella (causes bacillary dysentery) and entamoeba histolytica which is a protozoon (causes amoebic dysentery) Some cause enteric fever. Micro-organisms enter through the intestinal wall and disseminate to the blood and reticuloendothelial system causing septicemia and fever, and might lead to death. The micro-
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organisms that can do this are species of salmonella (enterica, typhi, paratyphi) We should know the pathogenesis of the infection of each member of the family, and how our body responds (the role of IgA and PMNs). Also it is important to diagnose the infection by different means of culturing on different media. And the most important is the treatment mainly by supportive therapy.
This is the general morphology of the enterobacteriacae. You can notice that it is a gram negative bacillus. You can also notice the O,H and K antigens. You can also notice the pilli which are responsible for attachment. There are different types of pilli; 1) Pilli binding to human enterocytes are called colonization factor antigen (CFAs) 2) P pilli are the ones that cause UTI 3) Type 1 or the common pilli 4) The bundle forming pilli (BFP) that bind to special receptors and inject the bacterial genes inside the cells
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Most of the enterobacteriacae come from humans, and you should know the ones that come from humans and humans only, like salmonella typhi. And you know the story of Mary Mallon which infected many people with typhoid fever in New York City. Others come from animals, like enterohemorrhagic E. coli that come from hamburger. *************************************************************
E. Coli intestinal infections There are 5 different serotypes of E. coli that cause intestinal infections, and these are genetically different from the serotypes of E. coli that are part of the normal flora. The 5 serotypes are: 1) Enterotoxigenic E.coli (ETEC) 2) Enteropathogenic E.coli (EPEC) 3) Enteroinvasive E.coli (EIEC) 4) Enterohemorrhagic E.coli (EHEC) 5) Enteroaggregative E.coli (EAEC)
1) Enterotoxigenic E.coli: It produces heat labile toxins and heat stable toxins. These toxins bind to a control unit we call it the GS protein, and the GS protein controls the activity of the adenylate cyclase enzyme, which convert ATP into cAMP, causing an increase of the level of cAMP. There is no control, and cAMP will be produced in a very large amount, and this will cause influx of water and electrolytes into the lumen and patients will have watery (non-invasive) diarrhea. Therefore no invasion or damage to the GIT is witnessed, just loss of water and electrolytes. Causes what we call traveler’s diarrhea, meaning that you get the diarrhea when you visit another country because you are not used to their food. Most Americans get this diarrhea when they visit Mexico, and there is a saying: if E. coli is green, then Mexico will be paradise.
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And remember, good physicians do not eat salad in restaurants, because you don’t know where the fingers of the worker who made the salad have been in the last 24 hours! So workers should wear gloves.
2) Enteropathogenic E.coli: This micro-organism doesn’t produce toxins, but binds by its Bundle Forming Pilli (BFA) to the microvilli. This binding will make changes to the microvilli and will interfere with the function of the microvili and absorption of fluids will be reduced in a way and the patient is going to have severe watery (non-invasive) diarrhea.
This figure is the description of the pathogenesis of enteropathogenic E. coli. You can see how the BFP is binding to the microvilli of the enterocyte, followed by the injection of the virulent factors into the cell, these virulent factors which are Esps and intimin receptors (toxin-like substanses) will change the shape of the microvilli, forming something like pseudopodia, thus, interfering with the microvilli main function of absorption. The pathogenesis of enteroaggregative E. coli is similar to this.
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3) Enteroinvasive E.coli: Genetically speaking, the enteroinvasice E.coli is very close to shigella, but the difference is that E.coli is motile and shigella is nonmotile. It produces Shiga toxins which are produced by shigella, the toxins cause damage to cells and interfere with protein synthesis, so inflammatory cells will reach the area causing damage and dysentery (invasive diarrhea). These organisms rarely invade into the blood, they invade the mucosa and the submucosa but they rarely reach the muscularis mucosa. This toxin is usually mediated by a plasmid, they cause -IPA plasmid.
4) Enterohemorrhagic E.coli: This is the most virulent serotype, it causes haemolytic uremic syndrome. Being infected has to do with eating raw hamburgers that are not well cooked in the restaurants, so it might contain some fecal contamination. They produce shaga toxin (like shigella), and this toxin affects the kidneys (causing renal failure), platelets (causing microthrombi) and RBCs (causing hemolysis).
5) Enteroaggregative E.coli: It’s a new E.coli, they aggregate like the enteropathogenic on the microvilli. The mechanism is similar to that of the enteropathoginc, they cause interference with the absorption of water and electrolytes so it will cause watery diarrhea. Worth to mention, we can rarely isolate those in the lab, most of cases of diarrhea will be misdiagnosed as viral gastroenteritis!
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This is a summary of what we were talking about (E. coli) and other enterobacteriacae.
Done by: Mohammad Abu 3assi 12
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Microbiology Food poisoning Cholera Ziad Al-Nasser Qutaiba Sabha Monday, 14/11/2011 24/10/2011
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*There were some repetitions and some ideas was scattered here and there. So, I did some rearrangement and summarization for the lecture. Forgive me for any mistakes *The Dr said that we should remember the microorganisms associated with the infection of the GIT, diarrhea, gastroenteritis and food poisoning. *The Dr started with a revision for the previous lecture. So, I put the additional information. Now, the pages are less. Ed3oolna ;)
Additional information on the previous lecture About enterohemorrhagic E.coli: 1- Mostly of the O157:H7 strain (O: somatic antigen, H: falgellar antigen). 2- Infectious dose: might need more than 10^6 microorganism to cause the infection. 3- Shiga toxin is also called "Stx" and it affects the glomeruli, platelets and RBCs. 4- Associated with invasive diarrhea like enteroinvasive E.coli. About enteroaggregative E.coli:
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They will aggregate on top of mucous films to make a natural barrier against absorption. The result is noninvasive watery diarrhea. These E.coli types are self-limiting (24-48h). The enteroaggregative may last 10-14 days. Extreme-age groups are very sensitive to loss of fluids. We shouldn't use antibiotics for the treatment of diarrhea unless there is an indication like severely-invasive ones.
Diagnosis of E.coli We have to think about the age group. Enteropathogenic E.coli infects the pediatric age group. DNA probes and PCR in the labs to identify those. *The next point wasn't well-explained by the Dr. It is a comination of the record, Hayat and wiki. E. coli O157:H7 (enterohemorrhagic) differs from most other strains of E. coli, like enterotoxigenic, in being unable to ferment sorbitol. In sorbitol-MacConkey agar, lactose is replaced by sorbitol. Most strains of E. coli ferment sorbitol to produce acid. Enterohemorrhagic is a non-sorbitol fermenter and it appears colorless on the plate. We do these diagnostic tests for E.coli when we have an epidemic or when we really need to know the diagnosis for a particular type of diarrhea. We don't routinely look |Page3
for pathogenic E.coli or think of it. That's why you should alert the lab specialists to look for them in such cases. Note: The rest of E.coli types will be discussed in the urogenital system. They cause UTI; cystitis and pyelonephritis. The pathogenesis depends on the types of pilli or the attachment proteins and the receptors in urinary bladder or the renal pelvis.
Again, the organisms that we are interested in are the pathogenic E.coli, Salmonella, Shigella (we look for Salmonella and Shigella routinely), Yersinia (not looked for routinely), Vibrio cholera (in cases of mass epidemic of severe watery diarrhea like those which happened in Afria and Somalia), Campylobacter jejuni (diarrhea) and Helicobacter pylori (causes gastritis, peptic ulcers and adenocarcinoma of the stomach). Other than those, the rest are normal flora like Klebsiella pneumonia, Enterobacter, Citrobacter, Proteus and Morganella. All of those are gram-negative Enterobacteriaceae. Sometimes, we see Acinetobacter and Pseudomonas aeruginosa in the stool and they are also part of the normal flora as well as environmental bacteria. It's extremely rare that those are associated with infection of the GIT.
Shigella  It causes invasive diarrhea.
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The classical example of the microorganisms that cause bacillary desentery. There are four different species of Shigella: 1- Shigella dysenteriae (group A): the most virulent one. 2- Shigella flexneri (group B). 3- Shigella boydii (group C). 4- Shigella sonnei (group D). Those are human pathogens. They don't infect animals. Transmitted through: 1- Fecal material. 2- Water. 3- Food. 4- Directly from one person to another (extremely rare). 5- Sometimes through flies. Infectious dose: very small. About 10-200 microorgansim could cause bacillary desentery. The infection is localized to the colon. Rarely, the Shigella can penetrate the muscularis mucosa or the serosa into the peritoneal cavity or the blood. So, we don't see Shigella in blood cultures unlike those of Salmonella. For example, Salmonella enterica Typhi can be seen in the blood, gall bladder and can be present in any part of our body. Usually infects people in over-crowded conditions, nursing home. Also, infects old people and people who can't clean themselves properly. Fecal-oral contamination can be easy in those areas.
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Pathogenesis
When a person ingests the miroorgansims, they pass from the stomach into the intestines where they can bind to specific receptors on cells.
In the figure, you can see the difference between Shigella and Salmonella. The Shigella microorgansims are taken inside the intestinal cells which are going to have actin rearrangement (part of physiology when the cytoskeleton can be rearranged in a way). So the microorganism inside can escape the phagolysosome in a way and they can pass basolaterally from one cell into the other through the actin rearrangement driving |Page6
force (actin tail in the figure). As you can see, it looks like a comet ( )مذنبor a rocket. That's how they can pass from one cell into the other. So, these can invade the cell, multiply in it and cause damage to it. Mainly, PMNs can be associated which will cause the bloody diarrhea and the mucus that we see in those patients. Many of those can produce the enterotoxin Stx (shiga toxin) which is also a cytotoxin. If we put this toxin on the conjunctiva, it will cause ulceration there. Despite this fact, the shiga toxin is not that important in the pathogenesis of Shigella. The main pathogenetic route is through the actin rearrangement and the firing of rocket-like microorganisms from one cell into the other. Listeria monocytogenes (which causes listeriosis) has the same mechanism to escape the immune system.
Diagnosis
Having signs and symptoms. Incubation period is short. Epidemiology: last mentioned point before pathogenesis int the lecture. Stool culture on MacConkey agar (differential medium). We look for the lactose non-fermenting colony. Also, Shigella is non-motile. Note: Shigella is very close to E.coli genetically. The difference is in motility (Shigella is non-motile whereas E.coli is motile)
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and lactose fermentation (Shigella is a non-fermenter whereas E.coli is a fermenter).  Biochemical tests.  Serology: to identify serotypes (A,B,C and D groups).
Treatment
Shigella is self-limiting. So, we only need water and electrolyte replacement. For Shigella dysenteriae (the severe one), we could use antibiotics (there is a debate about this point). We use 3rd generation cephalosporins, aminoglycosides, macrolides and ampicillin. We don't like to use tetracyclins. So, you have to use your clinical judgement about using these antibiotics. From Hayat: We use fluoroquinolones instead of ampicillin because Shigella might be resistant.
Prevention
It is the most important thing when it comes to these infections. It is done by improving the general hygienic conditions like personal hygiene, handswashing, proper toileting and washing fruits and vegetables. |Page8
Good physicians don't eat salads at restaurants. Always, you have to be suspicious of people working at restaurants preparing cold foods, salads and sandwiches. You have to think where the fingers of the food handlers could have been in the last two hours. The hygienic attitude of the food handlers is very important and they should use gloves all the time and they shouldn't use their gloves to scratch the perianal area which might lead to contamination. They think sometimes of making vaccines out of those to give them to old people and nurseries. But, some people don't really encourage that. They make hybrids of Shigella and E.coli as vaccine.
Salmonella We are going to talk about one species which is called Salmonella enterica. It has so many different serotypes: 1- Salmonella enterica Typhi serotype: associated with enteric fever (typhoid fever). 2- Salmonella enterica Typhimurium serotype. 3- Salmonella enterica Choleraesuis serotype. 4- Salmonella enterica Paratyphi serotype. (from Hayat) ***Here the Dr. should have talked about gastroenteritis but as usual he spent half of the lecture talking about enteric fever. These serotypes are called the enteric group (associated with enteric fever). This means that the infection goes through the GIT and bind to receptors on M cells in the intestines, and then |Page9
from there into the circulation and the blood through the reticulo-endothelial system and the lymph nodes. Then, the blood takes these microbes to anywhere in the body. They can infect WBCs (especially macrophages). They multiply inside the macrophages and use them to travel to other areas so that they can stay in our body for a longer period of time. Also, Peyer's patches can be infected. Look at the figure below, this is how the organism take ruffles and pedicels shape when it starts binding and how it is going to be taken inside to the reticulo-endothelial system.
Humans can be asymptomatic carriers. After recovery from the infection, those microorganisms can stay in the gall bladder.
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Typhoid fever
In typhoid fever, the patient will have a very high fever (39-40 degrees centigrade), splenomegaly, lymphadenopathy and rose spots skin rash (because of vasculitis). The symptoms that we see in the GIT are not specific. People could develop diarrhea, constipation or they might not have any symptoms at all related to the GIT. The fever is so characteristic. The fever is usually associated with tachycardia but here it is associated with bradycardia. So, we should think of typhoid fever when the patient's pulse rate isn't synchronized with his temperature. Normally, the minimum increase is from 10-20 beats per 1 degree centigrade increase of temperature. But, that's not the case in typhoid fever. The consequences of enteric fever are so high. They could develop vasculitis, thrombocytopenia, rupture of blood vessels or intestines, massive bleeding, septicemia and death. The mortality rate is high and they will tell you that this patient has died of fever, usually typhoid fever. Salmonella Typhi is resistant because it has a special type of capsule. The capsule has an antigen called the Vi antigen which can interfere with the phagocytosis so that the microorganisms can stay in our body for a longer period of time.
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The story of Mary Mallon (The Doctor's everyday story :S)
She was an immigrant from China and she used to work as a cook in one of the restaurants in the US. She used to carry the Salmonella Typhi (in her gall bladder) and thousands of people got infected because of her. When they did the epidemiological investigation, they traced all cases to Mary Mallon. They asked her to be treated but she refused. They fired her out of that restaurant. She went to another one and the misery continued. People eating at the other restaurant started to get infected with Salmonella Typhi till she got arrested and jailed. Then, she accepted the treatement for her carrier stage (treatment is done by a very large dose of antibiotics like ampicillin or by taking the gall bladder out; cholecystectomy).
Diagnosis
You can make the diagnosis by culturing the stool, blood, urine and body fluids in general. Blood is the most important specimen that we take to see Salmonella enteric Typhi. Where, you can isolate the organism after the 1st week. The technique here is so sensitive. That's why a single organism can be amplified and easily isolated. In the stool, you can isolate it during the 1st week, in the urine, after the 4th week. Serological tests are positive after the 3rd week when the body starts to respond by humeral immunity to it. You can see that septicemia takes the organisms everywhere. (see figue below for cultures). | P a g e 12
We used to do a serological test called Widal test. We don't use it anymore because it is not specific and insignificant. We rely upon isolating the organism in a pure culture; from blood, stool or urine.
Treatment of typhoid fever
We need antibiotics because it is a life-threatening situation (enteric fever not diarrhea and gastroenteritis): 1- Cholarmphenicol. 2- 3rd and 4th generation cephalosporins.
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***All of a sudden, the Dr. remembered that this is not HLS and he started talking about gastroenteritis.
Gastroenteritis (caused by Salmonella)
There are more than 1500 different serotypes of Salmonella enterica associated with gastroenteritis. The infection is limited to the GIT. Salmonella is the most common cause of food poisoning. Those serotypes differ from Salmonella enteric Typhi. Salmonella typhi is purely a human pathogen and we don't get it from animals while the other salmonellas that cause food poisoning and diarrhea come from poultry, birds, chicken (mainly), raw eggs and cream that comes from it (mayonnaise from raw eggs). Sometimes, we cut the infected chicken on the cutting board, then, we use the same cutting board to cut the fruits and vegetables on to make salads without cleaning the board in between. If the chicken was infected, the salad would be contaminated. That's why we should use different knives and cutting boards for meat or chicken and others for salads. This policy is used in King Abdullah University Hospital (KAUH). We get some of the Salmonellas by other animals like turtles. The excreta of them contain Salmonella and it could contaminate the turtle owner's food. Signs and symptoms of food poisoning appear after 24-48 hours (the next day) from eating the contaminated food. The patient will have abdominal pain, cramps, diarrhea | P a g e 14
and vomiting. Those will last for 24-48 hours (maximum of 3-4 days) then the patient recovers. Note: The incubation period for typhoid fever could take around 10 days but here, it is short (24-48 hours).
Diagnosis
 Salmonella is H2S producer and lactose non-fermenter. They can be easily identified in the lab by culture.  There is a selective medium called Salmonella-Shigella agar. But, we don't use it because when you see lactose non-fermenter and a black colony (H2S producer), then, the microorganism is either Salmonella or Proteus. Proteus makes swarming and produces urease enzyme while Salmonella doesn't. So, we can easily identify Salmonella in the lab. Note: Every Salmonella case must be registered in the public registery because it is a hygienic indicator and a massive food poisoning could be associated with it (epidemic). It helps to trace the origin of the poisoning (one restaurant that has contaminated mayonnaise). So, this has a significant epidemiological importance.
Treatment We don't use antibiotics. Simply, we replace fluids and electrolytes. | P a g e 15
Prevention
Maintain high hygienic measures. Handswashing. Spread awareness about how Salmonella can be transmitted from poultry and its products. Notes: It is preferred to buy chicken from the well-known factories. It would be much better than buying it from these local shops because sometimes, in these shops, you can't control the hygiene or the quality of meat that you are buying. ***el Dr. said 7aka enno ma beddo ye3mal commercials la 7ada fa ma 7aka asami factories. Kbeeeeeeer Ya Doc :D
Yersinia We have two microorganisms that are associated with diarrhea: 1- Yersinia enterocolitica. 2- Yersinia pseudotuberculosis. Notes: 1- Yersinia is in reference to Mr. Yersin, the discoverer. 2- Yersinia pestis causes plague which leads to septicemia and death. Xenopsylla cheopis flea is its primary vector.
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Yersinia is a member of Enterobacteriaceae (similar structure) and it is associated with gastroenteritis (the two types above). Yersinia has a bipolar staining (You can see that both poles can take the stain). Yersinia has outer membrane proteins which are considered as virulent factors. These virulent factors can be expressed when the organism is in an appropriate environmental condition. So, they can preserve energy. They get transmitted through food and water (those of gastroenteritis). When Yersinia infects the GIT, they also infect the draining lymph nodes associated it (mesenteric lymph nodes). After the infection, the patient could have abdominal pain, fever and rebound tenderness that could be misdiagnosed as acute appendicitis. Campylobacter can do that as well. So, when a patient comes to you with these signs and symptoms, you send to the lab to test the WBCs. Also, you see the urine or culture it to exclude UTI. You should observe the patient for acute appendicitis but you should also think of Yersinia and Campylobacter as organisms that could be associated with mesenteric lymphadenitis. *Rebound tenderness is a clinical sign that a doctor or other health care provider may detect in physical examination of a patient's abdomen. It refers to pain upon removal of pressure rather than application of pressure to the abdomen. Wiki *Rebound tenderness is how we test for acute appendicitis.
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*More than 30% of patients undergoing appendicectomy have normal appendices because of misdiagnosis. Yersinia and Campylobacter might be responsible for this by infecting the mesenteric lymph nodes. *Acute appendicitis is an emergency because if it ruptures, the patient will develop peritonitis, septicemia and death. Sometimes, if the appendix leaks, it causes adhesions and patients will end up with very bad complications. Yersinia can be treated with antibiotics; macrolides, fluoroquinolones and 3rd and 4th generation cephalosporins. But, most of them are self-limiting.
Vibrio
Vibrio cholerae is the causative agent of cholera. Vibrio is a gram-negative comma-shaped organism. It has one flagellum. So, it is highly motile. It survives in salty media (present in the sea). Seafood could be contaminated with Vibrio cholera and other Vibrios that cause food poisoning like Vibrio parahaemolyticus and Vibrio vulnificus that causes wound infection among sailors and fishers. They favor surviving in a high pH (8.5-9) which is the pH inside the lumen of the small intestine. So, it is the area where they attach, replicate and are found in. When we want to take specimens from pilgrimage or people in pandemics and epidemics, we use rectal swabs because Vibrio is associated with severe watery diarrhea. | P a g e 18
We insert the rectal swab in a tube called alkaline peptone water. It has to be alkaline for the Vibrio to survive. Species of Vibrio (from the table): 1- Vibrio parahaemolyticus: causes gastroenteritis, food poisoning and watery diarrhea. 2- Vibrio mimicus: causes watery diarrhea. 3- Vibrio vulnificus: causes cellulitis and wound infections. 4- Vibrio alginolyticus. Most of them are present in seawater.
Vibrio cholerae
This table is in the sildes (The Dr. didn't read anything from it). | P a g e 19
We subdivide it into many different serotypes: 1- Vibrio cholearae O1 (main serotype that causes cholera). a. Classical. b. El Tor ()الطور: It was isolated in El Tor area near Gaza in a pilgrimage camp. 2- Vibrio cholera non-O1: O139 which is a virulent strain. *The Dr. said O138 instead. But, in hayat and wiki, it is O139. So, I put it everywhere O138 was mentioned. Vibrio cholerae can cause severe massive watery diarrhea by the toxin they produce. The toxin is produced when the microorganisms bind thorugh their pilli into the small intestine. The pilli here are called toxin co-expressed pilli. Binding of the pilli triggers the mechanism of toxin's production. That's why we don't see vibrio cholearae toxin on its own so that we can drink it only and develop diarrhea like that of Staphylococcus aureus (can be present alone). We have to take a very high dose of those bacteria. The infectious dose is higher than that of Shigella or Salmonella. (Salmonella is about 10^5-10^6 oragnism). In Vibrio cholera, it is | P a g e 20
about 10^8-10^10 organism. This number of bacteria should get in and attach to the small intestine in order for the toxin to be excreted in that particular environment. Routinely, the stomach will take care of Vibrio cholera because it has a pH around 2 in which these organisms can't survive. So, you must have something to neutralize the acid in order for those organisms to reach the small intestine. People susceptible to getting cholera should be one of those: 1- Those who have problems in acid secretion in the stomach. 2- Those who undergone surgeries like partial gastrectomy. 3- Those who take antacids. 4- Those who ingested a very high dose of bacteria. Therefore, many of those could escape the stomach into the small intestine.
THE END
NO FOR US PRODUCTS YES FOR FREEDOM NO FOR FOREIGN INTERVENTION LONG LIVE WILLING PEOPLE
Done by: Abu Man9our :D I dedicate this to a flower ď Š | P a g e 21
38 / 59 3/9 20
Microbiology Bacteria of Diarrhea (cont.) and Viruses of Diarrhea Ziad Al-Nasser Mai Mazin & Samah Abu-Ghannam Wednesday, 16/11/2011
Microbiology - Lecture 3 Wednesday, 16/11/2011 Done by: Mai & Samah
Bacteria of Diarrhea (Cont'…) We will continue talking about microorganisms associated with GIT diarrhea. Today we will continue with vibrio cholera, we said that cholera is motile, favors salty alkaline environment, and it needs a toxin to perform a disease, so without the toxin there is no manifestation of cholera. So, cholera toxin is responsible for the disease manifestation In order for the toxin to be produced, the bacteria has to bind to a specific receptor in the small intestine, we call it GM1 receptor, where the bacteria binds and we have the Co-Expression factor (billi). The minute it binds through the billi, the toxin is going to be produced and this toxin of 2 major parts; A (active part or enzyme part) & B (binding part). So we have 5 subunits (3 B & 2 A ) so the B binds to GM1 ganglionic receptor then the A will pass into the cell then it activates the Adenylyl cyclase enzyme which converts ATP into cAMP and if cAMP level increases in amount then water and electrolytes will be poured from the cell into lumen. So normally, this enzyme has to be controlled and the regulation to this enzyme is through a special protein we call it GS protein, but what happens here in cholera is that this A component will cause ADP ribosylation of the controlling subunit GS so it will lose its function and the adenylyl cyclase will be continuously activated. So if we start measuring the solutes in the lumen we will find very low K and HCO3 (10 times more than the serum) while the Na is almost the same, so we can call it isotonic type of diarrhea. So the patient is going to have hypokalemia & metabolic acidosis. So, fluid will be poured out and there will be no inflammatory reaction and mucus will be coming out looks like rice, that’s why we call it rice watery diarrhea, and the patient might lose 20 liters of fluids per day :S , severe dehydration and if the patient could not compensate the loss of water & electrolytes at this level, he will die as a result of dehydration and its complications !
Diagnosis: Simply, we do not see one patient who develops cholera, usually it is a mass scale, pilgrims for example. nowadays no one develops cholera at least in our part of the world, maybe we still have cholera in other parts of the world in India, Bangladesh, Pakistan & Somalia especially at the time of famine & crisis & people moving from one area into another where they don’t have clean water so the water is contaminated with fecal specimens then they will develop cholera, because of no proper sanitary conditions, people get infected. Second, we have to culture and to see the patient is really having V.cholera, we have to do rectal swap into an alkaline peptone water (ph 8.5-9) then we transport that into the clinical micro lab. And there we have a selective type of media we call it TCS (TRYPTOSE SULFITE CYCLOSERINE) where the colonies will turn into yellow. We do oxidase test, it is positive for V. cholera, then we do some other biochemical & serological tests easily. Then we can determine the type O1 or non O1 and we add antibodies against O1 type.
Treatment: As I said, the treatment is by replacement of water & electrolytes … That’s It ! And people working in international relief agencies, they knew about that, they prepare these salty type of solutions that contain K & HCO3 to reverse the hypokalemia & metabolic acidosis, and the one we use here is the “Aquasal”. -
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What about using constipating agents ?! NO, because the root of the problem here is cholera toxin and the use of constipating agents is contraindicated coz the intestine will stop moving BUT the peristalsis movement is one of the defense mechanisms by washing out toxins so if we give those agents, toxin will stay & the problem will increase. So, what about using antibiotics?! In the past they thought about using tetracycline, nowadays we don’t use antibiotics at all, just replacement therapy and the patient will recover.
Prevention is the most important thing in controlling the disease, in the past they thought about vaccines to pilgrims they used dead organisms in those vaccines then they start talking about preparing B subunit and giving that to people so they will have antibodies against billi as a subunit vaccine, but most of these vaccines were not used at a wider scale.
Just what you need to do is simply the sanitary conditions, tell them how to use toilets, wash their hands, boil water if they have source of heat, or to chlorinate water if they have a source of chloride, so prevention is the most important, water disinfection, hygienic conditions … That’s it! What about the other organisms, the campylobacter and helicobacter. , those organisms also are helical, look like seagull, gram negative bacteria, part of normal flora of GIT of chicken & poultry like salmonella, so we get infected if we use the same cutting board for chicken and vegetables without washing it. And this organism, we call it campylobacter jejuni affected jejunum, it can be associated with mesenteric lymphadenitis as those of yersinia. We have a selective agar we call it camber plate (sheep blood agar with antibiotics) where we can isolate campylobacter. It causes mild, self limiting type of diarrhea but the problem with Ch. Jejuni is that it could be associated with the mesenteric lymphadenitis syndrome that we have talked about. And also they have noticed that the immune response could in certain cases cross reacts with the spinal cord, you can find this in many reports (you can check this on the internet) where we have Guillain–Barré syndrome when we have infection in the spinal cord, because of this inflammation of spinal cord is not well-known, sometimes paralysis could be associated with that. They noticed that this could be associated with Ch. Jejuni. Ch. Are sensitive to tetracycline, chloramphenicol, but most of them are self limiting and can the patient can recover without taking antibiotics .They could contaminate water, so we could be infected by water .so if the patients develops abdominal pain, mesenteric lymphadenitis, we have to think of these organisms before we think of acute appendicitis, we talked about that with Yersinia pseudotuberculosis, yersinia enterocolitica. It’s microaerophilic, it favors growth at 5% O2 conc. So it grows in thioglycolate media, and when we do gram stain we can see the seagull appearance of this organism underneath the surface of this media. The other organism is also looks like helical in shape, seagull as well. The one that we call H.Pylori, the causative agent of peptic ulceration & chronic gastritis. From where does this organism come ?!! we really don’t know, they have isolated this from oral cavity & sometimes from food . Why do people get colonized & others don’t !! We don’t know, so the epidemiology of those is not well-known but mainly it is related to oral hygiene in a way, so people with no oral hygiene could be contaminated with those organisms & maybe there are other factors which might help in colonization .. we really don’t know !
So, those organisms when they inter through the oral cavity into the stomach, they bind to the epithelial layer there, and they are very strong producers of urease enzyme which acts on urea splitting it into ammonia & CO2 and the ammonia elevates the PH neutralizing the stomach acidity so that those organisms could stay for a longer period of time. They have two important genes which are responsible for their pathogenesis: one is called vac gene from vacuolating agents making vacuoles in the epithelial layer of the stomach then chronic inflammation & then the ulceration that will follow that in the duodenum or the stomach. And the other gene which is called cag gene. They have noticed that the cag genes & the byproducts are going to have a transforming effect on cells, metaplasia will be the result. So, nowadays we have an oncogenic bacteria which is H.pylori, it can cause adenocarcinoma of the stomach. How are we going to make a diagnosis of peptic ulceration? From the clinical point of view: We have to prove the correlation between H.pylori and the signs and symptoms of the patient (hyperacidity, vomiting, nausea and sometimes diarrhea and melena). From the microbiological point of view: We need to prove the presence of at least ammonia and urease enzyme, to do this: -
We have what we call urease breath test; the patient blow in a simple instrument and we can measure the level of urease
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Or you can take a stomach biopsy, from the biopsy we can see the organism (helical shape, segal in appearance) and we culture them and also we can see the inflammatory reaction (gastritis) *It's enough to do one of them. How to treat peptic ulcer? By antibiotics. And we don't use just one type of antibiotics; we use a minimum of 3: Metronidazole (Flagyl), Amoxicillin and a Macrolide (like Clarithromycin). So, three antibiotics at the same time the patient has to take those for a minimum of 10 days. And on top of that, we add a substance called Bismuth sulfate. I remember they used to make a commercial for it: "the one that suits the one that protects". In 10 days the patient should be cured. In the past, we used to treat peptic ulcer by surgery; partial gastrectomy, vagutomy and so on.
Viruses of Diarrhea When I was at your age; we used to make the diagnosis of viral diarrhea by exclusion: We used to culture for Salmonella, Shigella, look for Protozoa, Parasites‌ If we excluded all these agents, we used to say: this is a viral diarrhea. We never even bothered to make the diagnosis at that time. It is extremely difficult to make the association because some viruses could pass through the GIT without causing a disease. So, to make the association: I. you must have positive correlation; every time you have the diarrhea, the virus is associated with that. II. You have to exclude other agents; bacteria or protozoa. III. The body has to interact; so you must have an immune response at least against those viruses. Nowadays, serology(1), electron microscopy(2) and immune electron microscopy(3) make the diagnosis of these viral agents so easy. About 30-40% of today's diarrhea cases are viral. (1)
Detecting the Antigen of the virus See the virus in a specimen under the microscope (3) Add Antibodies to the stool, they will bind to the virus then look at it under the electron microscope; it will be modified in a way) (2)
Children in particular are more susceptible of being infected with the viral diarrheas. Viral diarrhea is the second most common disease problem after the respiratory tract. Why we need to bother if children develop diarrhea? Because if those children develop diarrhea, they could be dehydrated and die. Part of your job as physicians working in the emergency rooms is how to treat a patient with gastroenteritis (vomiting, diarrhea, dehydration) and to learn how to calculate the amount of fluid and electrolytes needed to be given to the baby. The treatment in all viral diarrheas: replacement of the water and electrolytes through the IV line or giving the Aquasal (oral hydrating solution) if we are dealing with an older child who can drink.
Here are some words, no need to go through all that (yet the Dr. read them all): • • • •
It is thought that viruses are responsible for up to 3/4 of all infective diarrhoeas Viral gastroenteritis is the second most common viral illness after upper respiratory tract infection (both don't need antibiotics) In developing countries, viral gastroenteritis is a major killer of infants who are undernourished. Rotaviruses are responsible for half a million deaths a year (due to dehydration) Many different types of viruses are found in the gut but only some are associated with gastroenteritis
A. Viruses of diarrhea: All these viruses are: Naked and they have to be naked (remember: naked viruses are more resistant to environmental conditions compared to enveloped ones which can be easily destroyed by the low PH of stomach) RNA viruses except Adenovirus. Some single stranded, some double stranded. •
Rotavirus: makes the most of the cases of viral diarrheas. Rota means wheel because it looks like a wheel in shape. Belongs to Reoviridae family.
•
Adenoviruses; double stranded DNA. 2 serotypes: 40 and 41. Can cause cystitis.
•
Caliciviruses; Norwalk agents
•
Norwalk like viruses; Small Round Structured Viruses (SRSV)
•
Astroviruses; star shape viruses
And we have other modifications; Sapoviruses and Oroviruses (in the net: they are Sapoviruses and Noroviruses and they belong to Caliciviruses) 0T
0T
• • •
0T
SRV (Small Round Viruses) Coronaviruses Toroviruses
0T
B. Viruses that are found in the gut, not normally associated with diarrheas: • • • • • • • •
Polio viruses; in the CNS. Not associated with diarrhea although they have access to the GIT. Coxsackie A and Coxsackie B; could be associated with diarrheas Echo Enteroviruses 68-71 Hepatitis A; enterovirus not associated with diarrhea but the manifestation of the disease could come as a diarrhea Hepatitis E Adenoviruses 1-39 Reoviruses
C. Found in the gut as opportunistic infection: • CMV (Cytomegalovirus) • HSV (Herpes simplex virus) • VZV (Varicella zoster virus) • HIV
Talking about the viruses of Diarrhea:
You'll come across so many details regarding each virus. Important points are highlighted in colors if you'd like to take a look at the soft copy..
Rotavirus: -
Looks like a wheel (we can see a double capsid) The biggest of them all (80 nm in diameter) Naked, double stranded virus, 11 segments Belongs to Reoviridae Also found in other mammals and birds, causing diarrhoea Account for 50-80% of all cases of viral gastroenteritis (more than half of the cases!) The most common virus infecting children less than 2 years of age (In older age groups, think of the other viruses)
"Any baby less than 2 years of age develops diarrhea, it's Rotavirus until prove otherwise" -
Usually endemic, but responsible for occasional outbreaks Causes disease in all age groups but most severe symptoms in neonates and young children. Asymptomatic infections common in adults and older children. Symptomatic infections again common in people over 60 (although rarely we think of people over 60 developing the Rotavirus)
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Up to 30% mortality rate in malnourished children, responsible for up to half a million deaths per year (Remember: death is due to dehydration) 80% of the population have antibodies against rotavirus by the age of 3 (most people do get infected with rotavirus and usually they recover and develop antibodies) More frequent during the winter Faecal-oral spread. ? respiratory droplets (swallow it into the stomach) 24-48 hr incubation period (short)* followed by an abrupt onset of vomiting and diarrhoea, a low grade fever may be present.
*(It's important to identify the virus; with longer or shorter incubation period we have to think of other viruses)
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Diagnosed by electron microscopy or by the detection of rotavirus antigens in faeces by ELISA or other assays Live attenuated vaccines now available for use in children (very effective, especially people travelling into other areas where they could be infected)
It's extremely interesting how Rotavirus can cause the infection. Those viruses have what we call viral proteins (1-7), 4 & 7 are involved in attachment. When the baby is infected with Rotavirus, the low PH and the acid in the stomach can act on the attachment proteins and modify them (call them subviral particles) so facilitate their interance into the cell facilitate their replication (without the action of the acid on these proteins these viruses cannot replicate). Caliciviruses -
Much smaller single stranded RNA naked viruses, discovered in the 70s in a city called Norwalk in the US so called the Norwalk agents Infect older children Has a shorter incubation period (6-12 hours) and then the signs and symptoms of diarrhea and vomiting start to develop Small RNA viruses, characteristic surface morphology consisting of hollows. particles 35 nm in diameter Associated mainly with epidemic outbreaks of gastroenteritis, although occasionally responsible for endemic cases Like Norwalk type viruses, vomiting is the prominent feature of disease Majority of children have antibodies against Caliciviruses by the age of three Diagnosed by electron microscopy only, often difficult to diagnose because of their small size Treatment: the same; replacement of water and electrolytes
Norwalk-like Virus Particles -
Look like Norwalk agents Small RNA viruses, with ragged surface, 35 nm in diameter, now classified as Caliciviruses - Always associated with epidemic outbreaks of gastroenteritis, adults are more commonly affected than children Remember: 2 years of age: Rotavirus, more than that you have to think of others - Associated with consumption of shellfish and other contaminated foods. Aerosol spread possible as well as faecal-oral spread - Also named "winter vomiting disease", with vomiting being the prominent symptom, diarrhoea usually mild - Antibodies acquired later in life, in the US, only 50% of adults are seropositive by the age of 50 - Diagnosis is made by electron microscopy and by PCR In your practice you'll find that it's uncommon to come across viruses other than Rotavirus Adenovirus -
Causes sore throat and follicular tonsillitis with a very similar clinical manifestation to GABHS (pus). This could lead wrongly to prescription of antibiotics.
(?) How to know that this is adenovirus and not bacteria? It will be associated with infection to the conjunctiva (conjunctivitis). -
People normally can be infected with adenovirus without a need of treatment; it's a self limiting disease and patients will recover on their own Serotype 40 & 41 (called the enteric adenoviruses) in children can be responsible for cases of diarrheas Naked DNA viruses (the only ones that are DNA), large: 75 nm in diameter Fastidious enteric adenovirus types 40 and 41 are associated with gastroenteritis Associated with cases of endemic gastroenteritis, usually in young children and neonates. Can cause occasional outbreaks Possibly the second most common viral cause of gastroenteritis (7-15% of all endemic cases), after the Rotavirus Similar disease to rotaviruses Most people have antibodies against enteric adenoviruses by the age of three Diagnosed by electron microscopy or by the detection of adenovirus antigens in faeces by ELISA or other assays
Astroviruses
-
Small RNA viruses, naked, named because of star-shaped surface morphology, 28 nm in diameter (all of them around the same size except the Rota & Adeno) Associated with cases of endemic gastroenteritis, usually in young children and neonates. Can cause occasional outbreaks Responsible for up to 10% of cases of gastroenteritis Similar disease to Rota and adenoviruses Most people have antibodies by the age of three Diagnosed by electron microscopy only, often very difficult because of their small size Rarely we have antibodies to add to those viruses to do the immune electron microscopy
Coronaviruses (crown like, sun rays) -
Causes SARS (severe acute respiratory syndrome) so it's a respiratory virus and can cause gastroenteritis RNA viruses with a crown-like appearance Not convincing associated with gastroenteritis at present, so think of it as a differential diagnosis
Small Round Viruses -
Small virus-like particles with a smooth surface, 22-28 nm in diameter May possibly be parvoviruses, enteroviruses 68-72, or cubic bacteriophages Occasionally seen in the faeces of endemic or epidemic cases of gastroenteritis
The End
Nothing in the Nature lives for itself; Rivers don't drink their own water.. Trees don't eat their own fruit.. Sun doesn't give heat for itself..
Flowers don't spread fragrance for themselves.. Living For Others is the rule of Nature..
It doesn't matter how successful you think you are in life, how much money you have in your pocket or how many things you have brought. Just try and make others' lives more enjoyable, give every cent to the ones who are less fortunate and devote yourself to your community and to creating something that gives you purpose and meaning.. Life isn't all that long, and when you eventually die, you leave this earth with exactly what you came into it with; NOTHING. ُ ﺗﻧﻘُﺹُ ﺃﻋﻣﺎﺭُﻧﺎ ﺑﻳﻧﻣﺎ َﻧ ..ﻅﻥُ ﺑﺄﻧﻬﺎ ﺗﺯﻳﺩ .. ﻳُﺩ َﻓﻥُ ﺍﻷﻣﺱ ﺑﻛ ﱢﻝ ﺗﻔﺎﺻﻳﻠﻪ،ﻭ ﻣﻊ ﻭﻻﺩ ِﺓ ﻛ ﱢﻝ ﺻﺑﺎﺡ ٌ !ﺣﺳﻧﺎﺕ ﺃﻡ ﺳﻳﺋﺎﺕ ﻭ ﻻ ﻧﺩﺭﻱ ﻫﻝ ُﺗﺷ ّﻳ ُﻌ ُﻪ ُ ً ..ﻓﻁﻧﺔ ﺗﺟﻌﻠﻧﺎ ُﻧﺣﺎﻓِﻅ ﻋﻠﻰ ﺃﻳﺎﻣِﻧﺎ ﻣﻥ ﺍﻟﺗﻠﻑ ﺭَ ﺑﱠﻲ ﺍﺭﺯﻗﻧﺎ ُ َ ُ ُ ..ﺍﻟﺧﺳﺎﺋﺭ ﺍﻹﻳﻣﺎﻧﻳﺔ ﺑﺄﻗﻝ ِﻧﺎ ﻣ ﺃﻳﺎ ﻣﻥ ﺝ ﺭ ﻧﺧ ﺎ ﻧ ﻠ ﻳﺟﻌ ﻭ ﺍﺭﺯﻗﻧﺎ ﺫﻛﺎ ًء ِ ِ
Say Ameen ^^
Best of Luck :)
44/59 4/9 25
Microbiology Viral hepatitis Ziad Al-Nasser Hadeel Al-kofahi Thursday, 17-11-2011
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Micro lec # 4 Thursday 17-11-2011
Viral Hepatitis
Done by: Hadeel al-kofahi Today, we will talk about the rest of the viruses that are not associated with gastroenteritis but specifically infect the liver, so we call the infections caused by them [viral hepatitis]. The liver is affected by many factors: 1- Viruses: Many viruses cause hepatitis; of those we have [hepatitis A, hepatitis B, hepatitis C, hepatitis D, hepatitis E and hepatitis G]. We have receptor on the hepatocytes for those viruses and by those receptors the viruses can infect the liver. Other viruses can affect the liver are coxsackie virus , herpes virus and yellow fever virus that can be transmitted by mosquito then affect liver. 2- Chemicals. 3- Drugs: for example; ISOniazid {INH} that we use for TB, it’s hepatotoxic. some of the antifungal drugs {KETOCONAZOLE} can affect the liver, 4- Alcohol. >> Those chemicals can raise the liver enzymes like {AST and ALT} which are sensitive markers in liver injury in particular.
General comparison of the different types of hepatitis viruses: The virus type: HAV: ssRNA of the enteroviruses family [68-72] , but the virus 72 called the hepatitis A virus. HAV does not have the same manifestations of enteroviruses in function but the same structure. HBV: dsDNA HCV: RNA HDV: ssRNA HEV: RNA
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Percent of viral hepatitis: HAV: THE MOST COMMON {50%}. HBV: 41%. HDV: LESS THAN 1% HCV: 5%. HEV: LESS THAN 1%. HGV: extremely RARE. In the past when the doctor was at medical school, hepatitis viruses were classified as HAV, HBV and non-HAV, non-HBV, now the non-HAV and the non-HBV are the HCV, HDV, HEV and HGV.
INCUBATION PERIOD: [extremely important for differentiating] HAV: 15-45 days, in average of 25 days. Usually, It’s acute, no carrier states, no malignancies at all. HBV: 7-160 days, in average of 60-90 days up to 6 months sometimes [much longer period compared to HAV] HDV: 28-45 days. HCV: 15-160 days [similar to HBV]. HEV and HGV: unknown.
ONSET: HAV: usually sudden, acute, full recovery, with no complications. HBV: slow with complications like hepatocellular carcinoma. HDV: variable HCV: insidious associated with blood transfusion, with complications like hepatocellular carcinoma, chronic type hepatitis [chronic active hepatitis or chronic persistent hepatitis], liver cirrhosis and liver failure
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Age preference: HAV: children and young adults. HBV, HCV, HDV : All ages. HEV: young adults.
TRANSMISSION : HAV: fecal-oral. HBV: sexually transmitted, blood transfusion, blood and blood products, accidental needle injection, parenteral, vertical transmission from mother to her child by ingestion of the blood from the oral cavity when the baby is born or through skin abrasions. HDV: exactly the same as HBV. HCV: blood transfusion. HAV + HEV : fecal –oral HCV+ HDV : BLOOD TRANSFUSION HBV+ HDV: vertical transmission
CHRONICITY: HAV: none. HCV:THE MOST COMMON HDV: comes on top of HBV
CARRIER: HAV: none. HBV, HDV, HCV: patients can be carriers and Asymptomatic HEV and HGV: unknown
Immune serum globulin protective: we can give passive immunity for all of them depending on the severity 4
Hepatitis A virus: General features: It belongs to Picornaviruses {enteroviruses in general}. Positive sense ssRNA , it’s naked virus with CAPSID, it has viral capsid proteins for attachment to the hepatocytes, these proteins are {vp1,vp2,vp3,vp4}.
Transmission:
is FECAL –ORAL through the contaminated water by sewage system, and contaminated food, fruits and vegetables.
Can infect adults and children but mostly children.
Pathogenesis and clinical manifestations:
the child ingests the virus then goes to the small intestine then to the blood and through the blood into the hepatocytes, inside the hepatocytes there will inflammatory reaction leads to “cholestasis” associated with [ high fever, mild diarrhea (non-specific),
jaundice, dark urine, general weakness ,nausea ,vomiting].
Liver test: is positive for AST and ALT enzymes.
SERUM: conjugated-BILIRUBIN is high. Immunoglobulins against the capsid proteins: IgM starts the process followed by igG [with 4 fold increase in the titer]. Short incubation period : 15-45 days. The patient usually recovers and extremely rare that patients die by infectious hepatitis. There’s no sequel, no complications, no carriers, no malignancies, and the patient usually recovers. After infection, there are many inflammatory types of cells over the hepatocytes, those are responsible for fever ,general weakness ,edema, cholestasis, and urobilinogen that is secreted in urine forming the “dark-colored urine”.
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Also the patient will have clay–colored stool because there’s no bile or hepatic secretions into the stool in the intestine so mostly they go to the blood and excreted in the urine. In general If there’s no bilirubin in feces, it’ll be white in color.
Treatment and prevention :
what we can do for those patients is simply bed rest, high carbohydrate, sugar. But NO FAT DIET, NO PROTIEN DIET.
Vaccination: you can use “ Formalin-inactivated viral vaccines’ against HAV and it’s very effective, so this’s the mildest form of hepatitis that we can get.
From the picture, after a period of time, u can notice the liver enzyme [the ALT], the symptoms, the jaundice, HAV in feces, and u can detect serologically that u have viremia as well. And u can see the immunoglobulins, so 2-4 weeks after the infection u start to see IgM Anti-HAV and then start to go down, almost after 6 months it will be clear. While the IgG Abs start to go up and will stay for a longer period of time so it indicates that u have been infected with HAV , and in order to prove that u have been infected with the virus u must show 4 fold increase in the titer
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Hepatitis B virus: General features: The severest form of hepatitis that could lead to death is caused by HBV.
It belongs to family called the Hepadnavirus family, It’s incomplete dsDNA, [it’s incomplete so u have one segment which’s missing in the dsDNA and the smaller segment is the DNA polymerase].
It has many antigens like: Core antigen [HBcAg], E antigen [HBeAg], they are very important serologically to indicate previous infection, current infection and recovery. There’s Abs against HBcAg and HBeAg. The HBcAg is so difficult to be detected, but the Anti-C Abs [ IgM ] is the first antibody that we can see and it will last forever. So if you detect IgM-anti-HBcAg then this’s a marker for recent infection. While, IgG indicates that u have been infected in the past so there’s no much information we can get from IgG, but we can use it for screening purposes in blood banks for example , so if someone having anti- C Abs [IgG] we don’t take his or her blood for donation. The HBeAg has the same story, we don’t detect the E Ag we detect the anti-E Abs, and the Anti-E Abs indicate that the patients have been recovered so Anti- E is a good sign. The E antigen is a marker of virulence. HBV is enveloped, and the enveloped viruses can’t be transmitted through the GIT in babies but in adults they get disintegrated.
There’s also hepatitis B surface antigen [HBsAg] that binds to receptors on the hepatocytes, and this antigen we use for classification for epidemiological purposes. We have 4 different subtypes of HBV based on the nature of HBsAgs [adw, adr, ady …].
HBsAg is the first one that also we detect routinely in blood banks indicating whether we are infected currently or carriers of HBV. In the past we used to call it “Australia antigen”. The Abs against HBsAgs indicates the patients is on recovery.
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This’s the HBV, we call it [dane’s particle], it’s about 70-90 nm. You can see that viral envelope particle with HBsAgs has many different shapes of elongated or spherical that can be present on the patients serum with no nucleic acid.
The significance of the presence of HBsAgs in the enveloped dane’s particle, that u can take them and make vaccines out of them, and the vaccine is just simply the HBsAg, and it’s recombinant which u can take them from chronic carriers and use them as vaccines for pts. HBV has a long incubation period which could last up to 6 months or 160 days maximally.
The body will respond serology into the chronic hepatitis [active or persistent], liver failure. The chronicity usually in 20% of patients, so some patients could recover out of that , and those who develop chronic hepatitis are going to have hepatocellular carcinoma, and liver failure.
HBV causes a disease called serum hepatitis [ ]الكبد الوبائيbut the translations in Arabic is not right it should be [ ] الكبد البائي.
Transmission:
in adults, they have to have an intimate contact like transfusion, and sexual intercourse [very important heterosexual sex and homosexual sex, exactly like the HIV viruses], now we consider HBV the most common virus transmitted by sexual intercourse, and one of the venereal diseases is the hepatitis B.
Also it’s transmitted by accidental needle injection, So health care professional can get infected with HBV by accidental needle injection, so we have to be very cautious during handling them, and how we dispose the sharp needles, also it’s important to never recap the needle, and if u have to recap the needle we recap with one hand, so never recap the needle this’s role #1 in protection.
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Replicative cycle: The HBV has a process during its replication called the reverse transcriptase process and this process is not a conversion of RNA to DNA, it’s done by the DNA polymerase enzyme that can do the conversion of DNA into RNA and then back to DNA through its replication, and this process help the virus to integrate itself in the genome that’s why it’s considered one of the oncoviruses that causes hepatocellular carcinoma. The virus binds then enters inside the cell, then the nucleic acid(DNA) will enter the nucleus. The DNA polymerase is already linked to the virus, the polymerase synthesizes the missing portion of DNA and a double-stranded closed-circular DNA is formed in the nucleus. You can use the DNA polymerase as a marker as well so if u detect Abs against it it’s acute type of infection.
After a complete viral genome is transported inside the cell nucleus, mRNA and RNA copy will be transcribed. Then the reverse transcriptase enzyme will make a copy of DNA [ So DNA >> RNA >> DNA].
The mRNA is going to build the different proteins like the C and E and then HBsAg. Then it will bud out of the cell, usually packaging them through the ER and Golgi apparatus and then it will pass through the cell to outside.
Clinical manifestations :
the same as HAV; dark-colored urine, clay-colored stool, liver enzymes are on rise. The difference between HAV and HBV that the body respond to HBV by forming immune complexes [Abs binds to viral particles] and those they will precipitate in the microvasculature and the patients is going to develop vacuities and skin rashes.
9
The different AGs and Abs associated with HBV: [extra-notes next the table]
We detect the dane’s particle by the real-time PCR [the viral load], and the viral load is important to monitor if the patient is responding to treatment or not, and the treatment is with alpha-interferon, and digilated–interferon [the DOC for HBV]. HBsAg: the first one we detect , we use it as a vaccine, and the recombinant or the carries , the 4 different parts we use them for epidemiological purposes. HBcAg >> we don’t see it but we see Abs against it , we detect it by immunofluorescence inside the cell rarely outside the cell HBeAg >> marker of virulence , Abs against it is a marker of recovery Anti-HBs >> excellent markers for recovery Anti-HBc >> markers that u have been infected Anti-HBe >> good marker for recovery
10
From the picture : In the first 4-12 weeks, the first Ab that appears is the anti-C and u will have it forever. In the sec 4-12 weeks, the anti-E Abs appear. After that the anti-S Abs appear. [anti-E and anti-S are markers of recovery], so u can see the E and S antigens in the acute phase and then they’ll be followed by the anti-S and anti-E antibodies which are a good sign of recovering. While in chronic and carrier phases we don’t see Anti-S or Anti-E Abs, we only see anti-C Abs. also we have HBsAgs and HBeAgs.
Treatment: After making diagnosis serologically, we start treatment by: bed rest, relax the liver by high carbohydrate diet , low fat and low proteins. In general, when the liver fails we don’t use protein diet because in liver failure if the proteins are metabolized , the amino acids that are produced are going to cause encephalopathy, and u ‘ll study in the CNS when we do mental diagnosis in patients, it could be diagnosed as having psychiatric illness but in reality due to liver failure . Also we start using interferon-alpha and we monitor the patient with real-time PCR [viral load] to detect how many viruses still there after treatment, and we keep monitoring the patients till they get a zero load of viruses .
Vaccines: we have two types of vaccines [the active vaccination and passive vaccination]. The active vaccine starts from the first month of life, we give it in three doses called [0,1, and 6] this means the 0 doses at the start and one month apart we give the sec dose then 6 months apart we give the third dose, when u do that u r fully recovered. if we get an accidental needle injection we get an active and passive vaccine at the same time, So u have the active vaccine then the serum immunoglobulin, then passive Abs against HBsAgs, and we do diagnostic tests for serum markers starting with the HBsAgs , the anti C and we give prophylactic Abs against the S antigen in particular for ur own protection. 11
Everyone who come to the hospital for training should be vaccinated which’s very important for protection.
Hepatitis D virus:
HDV is called the delta virus. It’s a single stranded circular RNA virus, and it has an envelope of HBsAgs.
We need super infection or co-infection with HDV on top in patients already infected with hepatitis B virus or present as carriers of HBV, this will accelerate the scenario of the infection, and the disease become so severe, so HDV is an accelerator marker. HDV is much smaller than HBV and it has the delta antigen where u could have Abs against it so u can make diagnosis in the lab.
Transmission: parenteral, sexual, blood products like HBV.
Clinical manifestation: dark-colored urine and clay-colored stool , liver enzymes are going to be increased.
If u cure the HBV then by default the HDV is going to be cured on its own , there’s no special regimens to treat HDV, they tried a lot of anti-viral drugs that acts on RNA but the most important thing is to get rid of the HBV to cure the HDV.
Hepatitis C viruses: General features: HCV is an RNA virus of the flavivirus family. It has a core protein and envelope, and we have many different structural proteins on the surface, lipoproteins and non-structural proteins, these attachment proteins have phase variations by changing their shape so u could be infected more than once with these types of viruses.
Rarely, we see acute phase of hepatitis C , usually it’s insidious and the incubation period is so long could last to 180 days depending on the circumstances.
The patients can be carriers and can have chronic active hepatitis and the hepatocellular carcinoma, like those of HBV. it’s so difficult to make a vaccine out of the HCV not like that of HBV. 12
There’s increase in liver enzymes. HBV and HCV viruses are major viruses that account 90% of viruses that u need to know
Transmission:
It’s the most common virus that’s transmitted by blood transfusion and products so when we talk about post-transfusion hepatitis, it’s hepatitis C. Also it can be transmitted by sexual intercourse, vertical transmission [mother to child] like those of HBV.
Diagnosis and treatment: diagnosis by Abs against different attachment proteins [E1, E2, other surface proteins], and we have the real-time PCR to figure out the viral load, and treatment with digilatedinterferon. some peoples respond to digilated-interferon and interferon-alpha and some others don’t, that means there are certain genotype and genetics respond to that treatment and some don’t, and we have noticed that during treatment of hepatitis B and C. During blood donations, we look for: 1) hepatitis B and C. 2) we do PCR prior giving blood. 3) The Anti-C Abs is an early screener, 4) taking the history of the patient [any history of jaundice we don’t give blood for donations, sexual intercourse and sexual promiscuity, infections]. sexual promiscuity means having more than one sex partner [male or female].
So it’s important to educate the people about sexually transmitted diseases.
Clinical manifestation: In chronic active hepatitis, you’ll see so many lymphocytes predominance in the liver and the edema that’s associated, also the clay-colored stool and the dark-colored urine.. from the pic: these are the serological markers and the symptoms, notice the liver enzymes how they increase to extreme then they fluctuate but usually they respond to Anti-HCV Abs on the rise that will stay for a longer period of time. Also u can detect the RNA of the hepatitis C virus by the viral load to see if the patient is responding to treatment or not. 13
Hepatitis E viruses: It’s RNA virus. Transmitted by fecal-oral route. it has a long incubation period It’s so difficult to make a diagnosis with hepatitis E but u have to think of it, as one of the viruses associated with hepatitis and jaundice. hepatitis C virus is a calicivirus and one of the RNA viruses as well that’s not recognized well in labs routinely , we have to think of that in cases of epidemics and where those viruses are located in areas of south east countries [ India, Pakistan ] where we have to think of those.
Hepatitis G viruses: HGV is a new virus , that we don’t know much about and added up to the set of hepatitis viruses. And u start to think of HEV and HGV when u fail to diagnosis A, B, C or D because those can be easily identified. Note: the doctor said >> Read about the hepatitis cuz they are extremely important and the bulk of the Qs in the exam are coming from them.
The End Every successful person has a painful story, every painful story has a successful ending, so accept the pain and get ready for success Words are not enough to thank everyone who helped me <3
Best of luck All Done by: Hadeel Al-Kofahi 14
47/59 5/9 30
Microbiology Schistosomiasis & Parasites of GIT Ziad Al-nasser Deeb Zahran Sunday, 20/11/2011
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Microbiology lecture 5 Sunday, 20-11-2011 Done By: Deeb Zahran
“Schistosomiasis” We will talk about Schestosomas in two systems, the GIS and the UGS. There are five species of Schestosomas that can infect humans. Two of them, S.
mansoni, S.
manifestation
to
the
japonicum
are associated with infection and
GIT.
haematobium
S.
is
associated
with
manifestations to the urinary tract. While the remaining two species; S. intercalatum, S. mekongi are not of that importance. Schestosoma is one of the Trematodes (or Flukes); means body with holes. Those flukes in general are either hermaphrodites, means that the male & female genital organs locate in the body of the fluke, or have separate sexes, where eggs produced after copulation. Schestosomas have separate sexes; the male and female present in a Copulatory embrace. They have a cylindrical shape. The female is always about 1 cm in length, while the male is shorter than that ... (In the book, the male is 2-3 cm in length, and the female is even longer!). The male contains canal called Gynecophoral canal that harbors the female, so the female is embedded inside the male’s Gynecophoral canal. See the figure next page. Both of them present as a Schestosomal couple in the portal vein (so, called Blood flukes), which is their main habitant that they survive in for years without even being detected by the immune system, as they cover themselves by RBC’s and HLA antigens so they cannot be recognized. This couple has a ventral sucker and an oral sucker which are used in these worms for locomotion, so they bind and walk even against the blood flow to their Oviposition distention for the female to lay down eggs.
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So, the portal vein isnâ&#x20AC;&#x2122;t the position for laying down eggs; the female instead has to move away from the portal vein. And we can identify and so differentiate those mostly by the shape of their eggs.
This is another view of the Schestosomal couple, with the female is embedded in the male. Here we can see the infectious stage, itâ&#x20AC;&#x2122;s called Cercaria that comes out from the snail and looks like a sperm. It swims in water and can penetrate the skin of humans, which is the rout of infection by Schistosomes.
Itâ&#x20AC;&#x2122;s by eggs that we differentiate between types of Schistosomes: - The eggs that cause infection to the GIT (eggs of S. mansoni) are very large, with the larva inside called miricidium, its dimensions are 140 and 60 Microns in length and width. They have a lateral spine.
- These eggs are for S. japonicum. From its name, it presents in Japan and south-east countries of Asia. It has a lateral small node compared to the spine of S. mansoni.
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- Eggs of S. haematobium have terminal spine. It’s the one seen in urine, and associated with manifestation of urinary tract.
So, in this lecture, the talk will be in S. mansoni & S. japonicum as they’re associated with the GIT, leaving S. haematobium to the UGS. These Schistosomes present worldwide, especially in tropical areas like The Delta Nile in Egypt, South America, & East Asia. It’s spreading where there is rise agriculture, because rise need to be covered with water all the time, and in water we have water Snails, so, if somebody is walking barefooted in the rise fields, he could be infected with those Cercaria (the infective stage). As well as walking or swimming in brackish water ( )الترعwhere they have the Cercaria, it’s a source of infection also.
The life Cycle
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As we said, the Schestosomal couple inhabits the portal vein. The portal vein is supplied by two major veins, the superior and inferior mesenteric veins. - The Superior mesenteric drains the small intestine, secum, ascending colon, and two thirds of the transverse colon. - The inferior mesenteric drains what left of the GI tract (except the lower part of the anal canal) with the urinary balder. After mating in the portal vein, S. japonica use their suckers to walk against blood flow, choosing the superior mesenteric veins to travel to its destination (small intestine, secum, ascending colon, and two thirds of the transverse colon), allowing the female to laying down her eggs there. The case is different when talking about S. mansoni & S. haematobium, which after mating in the portal vein, use their suckers to flow against the blood flow choosing the inferior mesenteric to their destination (what left of the GI tract, with the urinary balder), allowing the female to laying down here eggs too. *Note here, lying down eggs from the females will be still in the veins. From their destination, the eggs will penetrate through the walls of the veins into the lumen. The larvae inside (miricidium) will produce enzymes that will facilitate the process of eggs penetration. From there, the eggs will go through fecal materials outside. So, if people have indiscriminate defecation, like in the fields, these eggs will go into water, where the miricidium will go out, and then they will be eaten by water snails. The miricidium will go over different stages of development that will end up with Cercaria which will swim in the water. So if somebody is walking barefooted or swimming in the brackish water, the Cercaria will penetrate through the skin. When doing that, the Cercaria will lose its tail and body; ending up just with the head (itâ&#x20AC;&#x2122;s called then schistosomula) under the skin, staying there up to 2 days. Then they will go through venous blood, then the arterial blood, through the lungs, ending up in the portal vein, some as males and others as females, then copulating. Page 4 of 16
Here is the snail. Within it, development of the miricidium will take place through sporocysts, ciria1, ciria2, and cysts stages, ending up with Cercaria.
Pathogenesis and clinical manifestations 1) In the early stage, where the schistosomula are present in the skin within few hours, infected people will start Itching (swimmer’s itch). 2) In the intermediate stage 1 - 2 months after exposure, when the female leaves the male for the Oviposition, occurring in the terminal ends of the superior & inferior mesenteric veins. The female here will start laying down her eggs. The body will react upon that, so a type 1 hypersensitivity reaction will take place, & IgG, IgE, Immune complexes, complement activation will develop (that’s what the doctor said exactly) & the patient will have Edema all over with skin rash. In Japan, they call this stage katayama reaction. 3) Chronic stage. This the most serious stage and the one people die of. It’s represented by the entrapment of eggs. It might be entrapped in the colon walls while it’s trying to pass through the feces to the outside, and the body will start to react against, so a chronic granulomatous type of a reaction, pain, & bloody diarrhea. This case doesn’t kill. Killing occurs when many of those eggs are washed back by the superior & inferior mesenteric vein into the liver and get trapped Page 5 of 16
there. So, the body will develop a pre-sinusoidal fibrosis, chronic granulomatous type of a reaction, granuloma, ending up with liver failure and death. The first manifestation will be portal hypertension, and then plasma cells will start oozing out of the portal vein into the peritoneal cavity, and the patient will develop Ascites (accumulation of fluids in the peritoneal cavity).
Epidemiology of Schistosomiasis - More than 200 million people in 74 countries are infected. -
Usually there are Less than 10 pairs in one patient, with “more load more symptoms”, because more loads will present with more eggs. The infection hasn’t anything to do with the presence of those in the blood, they are asymptomatic there. But the problem is the eggs and it’s entrapment in the intestine, the urinary bladder, or the liver.
Immunity - Cell mediated immunity involvement. - It has a genetic susceptibility with HLA type A1 & B5. - With the protective IgE antibodies that are produced, and the one responsible for the katayama reaction.
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Diagnosis - In case of S. mansoni & S. japonica, itâ&#x20AC;&#x2122;s done by stool analysis, looking for the ova & eggs. If the stool is negative, we can take a biopsy. - In case of S. haematobium, we look for eggs in the urine. And if it was negative, we do Cystoscopy (examining the interior of the urinary bladder) to get a bladder biopsy. - Also we can detect immunoglobulins against some of the antigens of the wormâ&#x20AC;&#x2122;s body, as a serological diagnosis.
Treatment - If the infection reached the third stage (Chronic stage), the treatment will not be effective at all. - In the early stage, we use anti inflammatory drugs, corticosteroids, & local anti-histamines to alleviate the inflammation. The Adult worms can be killed by the drug of choice praziquantel, or we can use metrophonate.
Control and prevention 1) The most important step is not to walk barefooted, or swim in the brackish water Cercaria is expected to be present. 2) Educate people about the life cycle, so that to stop throwing the fecal material in water. 3) Trying to control the snails by using molluscicides, so to get rid of the snails, and this is very difficult to do. 4) Skin protecting while doing farming by wearing sleeves and shoes. They have tried to make vaccines against the Cercaria (the infectious stage).
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“Parasites of the GIT” We are going to study some of the parasites, and we will start with the protozoa that infect the GIT like: 1) Entamoeba histolytica as an example of Amoebaes. 2) giardia lamblia 3) Cryptosporidium pardom These are the commonest protozoa associated with diarrhea, though we have others like Balantidium coli which is the largest protozoa, it comes from Pigs and is associated with gastroenteritis, but in our part of the world the upper three protozoa’s are responsible for manifestations of the GIT diarrhea & dysentery.
Entamoeba histolytica - This protozoan belongs to a group called the Rhizopoda. And those move using false poda (pseudopodia). - They are present in two stages, the trophozoite stage and the cyst stage.
The trophozoite has one single nucleus with a central nucleolus, and evenly distributed chromatin material around it. Other protozoa have irregular shaped nucleus and chromatin, which really helps in the diagnosis of those protozoa. We make the diagnosis from the shape of the nucleus mainly (it looks like Bulls eye). Page 8 of 16
We have red blood cell inside, and the cytoplasm is vacuolated compared to the other nonpathogenic types.
Its ectoplasm (part of the cytoplasm related to the psuodopod) is around 10 micrometer, and the total length of it is 30-40 micrometer in average.
The trophozoite stage is the (disease causative stage).
The cyst stage (the infectious stage) is circular, we can have more than one nucleus (up to 4 nuclei, no more), and we have aggregates of ribosomes called “chromatin bodies”
When you look at the trophozoite, the first thing that attracts your attention is the nucleus, and of course the irregular shape of this stage (while we have circular shape in the cyst stage and we also have multiple nuclei and chromatin bodies).
Very important: When you see more than 4 nuclei in a protozoan, then by definition it’s not Entamoeba histolytica, it’s mainly Entamoeba coli (common type that is not associated with disease). Regarding this point; once you see Entamoeba coli or other nonpathogenic cells of this category in the stool, this means that this person has ingested fecal contaminated food, because those are not part of the normal flora.
So, we have to know the other nonpathogenic amoebae, because Entamoeba histolytica is the only pathogenic one which actually causes amebic dysentery. *dysentery means: having the urge to defecate, but when defecating, the patient will only pass few drops of mucus blood feces. Page 9 of 16
Note: Until now, we know these etiologies of dysentery: Shigella (bacillary dysentery) Schestosomal dysentery Entamoeba histolytica dysentery.
Trophozoites have lectins around them and they use them to bind to specific receptors in the colon, then they produce enzymes (like cystine proteases) that cause invasion of the colon. Based on that, and beside the shape, you can differentiate the pathogenic from the nonpathogenic types of Amoebaes by running enzyme analysis and identify those specific enzymes that cause the symptoms.
Nonpathogenic Amebas: Entamoeba coli, Entamoeba dispar, Entamoeba hartmannae, we also have Iodamoeba bütschlii.
Entamoeba histolytica is associated also with ulcerative inflammatory lesions in the colon which are also responsible for the dysentery manifestations.
Entamoeba histolytica can also do ExtraIntestinal traveling (outside the intestine), and the most favorable organ to go to is the liver, causing Entamoebic Liver Abscess. So liver abscess might not be caused by bacteria; it also might be caused by Entamoeba histolytica. We will see 5% of those who have Entamoebic dysentery will develop Entamoebic Liver Abscess.
It’s contains many enzymes that can be used for identification: - Glucose phosphate isomerase. - Phosphoglucomutase. - Oxidoreductases which are the zymodemes.
Its length is from 10 – 60 μm (40 as an average), and it has glycogen (when you stain it with iodine it will give dark-brown to black color).
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The Life Cycle We start with a cyst stage, where we have a mature cyst. How many of those we need to initiate an infection? - About 1000. Although, it has been proved that 1 cyst is enough to cause infection! - Those can resist the normal chlorination of water, and can resist the low pH of the stomach. >> So theyâ&#x20AC;&#x2122;re highly infectious.
How do we get infected? By eating vegetables & fruits that are not well washed. So we all should remember the story of the good physician and the last two hours :) After ingesting the cysts, they will go through the stomach & the small intestine to the ileum, where they will exCyst. Then the trophozoites will go to the cecum and colon, where they will produce the zymodemes enzymes, and then they start to cause lyses of the epithelial layer, the mucosa, submucosa, up to muscularis mucosa. They cannot penetrate through the muscularis mucosa, so they will go sideways, leaving an ulcer of a flask shape; has a small opening & a wider end. Then the trophozoites will inCyst again in the colon, and then they will leave through fecal material outside where they could contaminate vegetables, Page 11 of 16
fruits, or water. So, humans will get infected if they ingested food contaminated with Cysts. It also proved that those cysts could by sexually transmit among homosexuals. What is important here, that each cyst that has 4 nuclei (maximum), could end up giving 4 trophozoites, and the trophozoites will multiply, ending up with so many of those. This counts for it highly infectivity. As a summary of the life cycle: Cyst>> exCystation in the small bowel >> trophozoites in large bowel >> cysts again.
Epidemiology - 10% of the world population is infected each year. - Associated with some cultural habits, sanitation, crowding, and socioeconomical status (very common in third world countries). - Sometimes patients could be asymptomatic, so they can carry and transmit those to others. - Male homosexuals could be a source of transmition. - Amoebas can carry HIV virus, so, HIV virus could remain viable within the amoeba. And here, the amebas can act as Mitogens (stimulating mitosis), that mean they could stimulate the T-Helper Cell. Itâ&#x20AC;&#x2122;s noticed that HIV patients when getting infected with Entamoeba histolytica, the scenario of the asymptomatic phase of HIV virus will be shorter, since itâ&#x20AC;&#x2122;s enhanced by the act of amebas. There will be short asymptomatic phase instead of an average 7 years; it could be 2 or 3 years! - Children with malnutrition are susceptible to be infected.
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Here the doctor started just to read the slides, without that much clarifying! Am sorry if it’s hard to understand.
Pathology and pathogenesis - Lytic effect on tissues from zymodemes. - Amorphous, granular, eosinophilic material surrounds trophozoites in tissues including neutrophiles → and then they release toxic products → tissue destruction, overall protective role of the immune system. - Spectrum of colonic lesions ranges from non specific lesions to flask ulcers. - Liver necrotic abscesses, periportal fibrosis. - Adherence start with (lectin – mucin) → proteolytic effect → resistance to host effectors mechanisms (C5b-9) & they can resist the effect of the complement in a way.
Host immunity - Recurrence could develop in those patients. But the 2nd time it’ll be shorter. - High antibody titer following amebic liver abscess & this is how we make the diagnosis, by imaging technique, serology, and sometime by biopsy from the liver. - They resist complement. - Secretory IgA (sIgA) protective effect, CMI (cell mediated immunity) and lectin Ag role of corticosteroids. If we use the corticosteroids we’ll suppress the cell mediated immunity, and thus enhancing the infection. - We can grow those on artificial media to study vaccines of them, but till now vaccination are not successful.
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- Mucin and mucous in the colon plays a major role in protection. So why some people get infected while other donâ&#x20AC;&#x2122;t still a mystery that has not been resolved yet.
Clinical Manifestations - From Non invasive manifestations into invasive amebic dysentery. - Abdominal pain, tenderness, bloody stools. - Fever only in one third of those, it depends on the tissue damage that the patient have. - Liver is enlarged if infected. - All patients have heme positive stools because of the ulcers they developed, while some will have rectal bleeding without diarrhea. - Fecal leukocytes might not be present. *We differentiate between invasive diarrheas VS. non-invasive diarrheas by Fecal leukocytes. - Fulminant colitis might need colectomy. So some time you need to remove the whole colon! (Fulminant colitis is any colitis that becomes worse rapidly). - Intestinal perforation; and this perforation sometimes could lead to dissipation of fecal material into the peritoneal cavity causing peritonitis. -
Toxic megacolon.
- Because of the chronic granulomatous reaction, sometimes tissue could protrude inside the colon, we call it ameboma. Physician always think of that as a tumor, but when they take it out, they found that itâ&#x20AC;&#x2122;s just a granulomatous tissue reaction against Entamoeba histolytica.
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Here you can see the massive ulceration caused by Entamoeba histolytica. It might need colectomy.
Diagnosis We make the diagnosis by finding trophozoites or cysts in stool. And it is easier to see the cysts than to see trophozoites.
The End
.. السكينة و الضّ ياء ّ اكن ّ يتبادالن لغة.. الصباح رفيقه يف ذاك الطريق .. ّّ ممتهّل ْي اذ م دجاا بببا يراحا للّّج .. هو شارد ّاذلهن .. يف لوحة م يُمك رمس شجاع ال ّشمس فهيا بجا .. مجىن من مجاين امجلال يصفها ِ يف ّقصة م ً يار بأ ّي .. امليض قاما حنو الم ّ عه ٌا عىل.. يف الجها .. يف حرضة املس ّقب املنشود .. توقّف حلظة . و يبتسم.. لينظر يف الطريق الطوي Malik & 7amzeh .. shokran :) Your colleague .. Deeb Zahran Page 15 of 16
47 / 59 6/9 20
Microbiology Parasites of GIT Ziad Al-Nasser Aya Al-Nobani Monday, 21/11/2011
1
Microbiology Lecture # 6 Aya al nobani
Protozoal infections Entoemiba histolitica Last time we started talking about the Entamoeba histolyticaand we figured out how this organism is associated with amoebic dysentery ( bouts of diarrhoea and tenesmus) and we talked about the life cycle , the pathogenesis how the trophozoite can act on the mucosal layer and causes ulceration (flask shaped ulcer) so that there will be alternation between normal and abnormal mucosa. Complications: amoebic liver abscess (5% of the people having the amoebic dysentery will develop this liver abscess ) and itâ&#x20AC;&#x2122;s usually in the right upper lobe and u can make the diagnosis of these through imaging techniques , serology and aspiration of those abscesses which will consist of pus containing brownish trophozoite and not many PMNs with them. **aspiration of the liver abscess is considered as a way of treatment as well as diagnosis Sometimes the left lobe may be affected and since itâ&#x20AC;&#x2122;s close to the heart , these abscess may penetrate through the diaphragm and into the pericardium which might lead to cardiac damage ,cardiac tamponade and pericarditis. Clinical presentation: varies from asymptomatic carrier to severe ulceration of the GI tract , depending on the immune status of the patient, so if the patient is cell mediated immune deficient usually the consequence are catastrophic that you sometime need to take out the whole colon Diagnosis: is simple, just finding the trophozoite or the cyst . the trophozoites are sometimes difficult to see in the stool but they can be seen by doing an endoscopy; 2
sigmoidoscopy ,colonoscopy. Cysts can be seen in the simple stool analysis , and nowadays we have the antigen detecting technique (serology) where u can detect the Entamoeba histolytica antigens, if did … smear and stool examination and it was negative then we can do an endoscopy Differential diagnosis: you have to differentiate amoebic dysentery from the ulcerative colitis and crhon’s disease and the main difference is that in ulcerative colitis the ulceration is usually homogenous all over while the amoebic is alternating ( normal tissue in between the ulcer and this normal tissue contains lots of trophozoites of Entamoeba histolytica) while in crohn’s disease you can see more granulation (it’s though that crohn’s disease is related to one of the mycobacteria but it’s still classified as autoimmune (in patho it’s idiopathic not autoimmune ) Morphology of the trophozoites: large around 40-60 in diameter, nucleus with even chromatin material, it contains red blood cells that it has ingested Morphology of the cyst : 4-5 nuclei , chromatin bar which are blunted and not pointed (entoemiba coli they are pointed ), aggregates of ribosomes 11:40 what something about the pic is by definition is entoemiba coli not histolytica
Entamoeba histolytica , the typical bull’s eye appearance 3
Entamoeba hartmanni and Entamoeba dipar: the same as Entamoeba histolytica but smaller and we don’t see RBCs in the trophozoite Entamoeba coli: the nucleolus is exentric and the chromatin material is irregularly distributed Endolimax nana the nucleolus is large and you don’t see chromatin bars in the periphery Dientamoeba fragilis : one of the protozoa causing gastroenteritis , you can see just dots without the chromatin material Iodamoeba buetschlii : same as Endolimax nana but you can see a very big glycogen vacule inside the cytoplasm Treatment : the drug of choice is metronidazole (flagyl) which has some side effects: 1. it’s contraindicated such as in pregnancy – it has teratogenic effect 2. metallic taste 3. Disulfiram -like effect : if the patient is taking alcohol , he will be tired with nausea and vomiting >> wiki : Disulfiram is a drug discovered in the 1920s[1] and used to support the treatment of chronic alcoholism by producing an acute sensitivity to alcohol Other drugs we can use (if the patient is not responding to flagyl or it’s contraindicated): Dehydroemetine (the drug of choice after the metronidazole), Diloxanide furoate (an antibiotic that have synergistic effect to the metronidazole), paromomycin (we use this for the Cryptosporidium as well), tetracycline (to wipe out the normal flora which the amoeba use as food), Tinidazole. We treat the asymptomatic carriers, if we test the food handler and they were positive, we have to treat. But we have differentiate between it and the entamoeba dipar because in the case of entamoeba dipar we don’t treat Stool analysis is important to follow up the treatment till they are negative Drainage of the liver abscess (surgery or under x-ray imaging guidance) Prevention Like most of the GI infection it’s transmitted through the fecal–oral rout, so preventing the disease is done by:
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Good sanitary conditions Washing Vegetables (lettuce) (kol 3edet el salata: P) with water and chlorine. Using strong detergent soap, soak with acid (hypochlorus). Only boiling of water is effective. Proper waste disposal and water purification. Sexual practices ; homosexual and oral-genital sex, which might be a way of transmission
Giardia lamblia It’s one of the flagellated enteric protozoa. It can be present as trophozoite and cystic forms ;The trophozoite is around 9-21 µm in length and 5-15µm in width (three times the size of an RBC or double the size of WBC), and it has 2 nuclei and nucleoli inside and sucking disc (used to attach to the microvilli) around it and 8 flagella in 4 pairs; anterior , lateral, ventral, posterior , parabasal bodies , axoneme , if you look at it carefully , it looks like someone is looking at you (clown face ) with moustache and whiskers. Because there are flagellated when you see them under the microscope, you can notice the repelling giardial movement The cyst stage (the one that cause the disease) is shorter than the trphozoite; it has up to 4 nuclei and nucleoli inside, parabasal bodies and axonme as well. It is oval in shape and can be easily identified. In the routine stool analysis we see the cyst stage in 99% of the cases but the trophozoite are seen during endoscopy or the string test string test : involves a gelatin capsule connected to a weighted nylon string, the patient tapes one end of the string to his cheek and then swallows the capsule. After the gelatin is dissolved in the stomach, the weight carries the string into the duodenum and it is left there for 4–6 hours or overnight while the patient fasts. After removal, the string is examined for bilious staining, which identifies successful passage into the duodenum. The mucus from the string is examined for trophozoites in iodine or saline. Wiki …
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Pathogenesis: we ingest the cyst stage , they go down to the stomach (they can tolerate the acidity) then into the small intestine where they divide to produce 4 (in the book 2 ) trophozoites which divide as well , then they will bind to the micro villi through the sucker body , the binding of this organism is so interesting , it’s not only mechanical , it’s also associated with disaccharide malabsorption , so the patient might develop milk intolerance (lactose intolerance ) causing the symptoms of abdominal cramps, diarrhoea, flatulence and pain. Non-invasive diarrhoea, an immune reaction against the microvilli can develop, so we can see Ig Symptoms: You have to remember that these organism infect the small intestine and cause destruction to the microvilli as a result the patient will develop malabsorption , severe watery diarrhoea ,problems in lipid digestion and absorption and steatorrhea (which mean a lot of fat floating over the toilet water ). Epidemiology
Incubation period : 5 days – week Disease can last for 2 to 3 weeks It infects both animals and humans. Causing both Endemic and epidemic diarrhoea, in places where you have animals, so people might drink contaminated water. It’s from the Zoomastigophora class; G.lamblia is the pathogenic one , intestinalis, duodenalis, these are not associated with the disease . And there’s antigenic variation among them. Diagnosis: stool analysis and we look for the cyst stage , endoscopy &string test we look for trophozoites You can Culture in presence of biliary lipids to get more of the antigens that we can use for diagnostic purposes Treatment: water and electrolyte replacement DOC; metronidazole(flagyl) for 10 day to 2 weeks 6
alternative drugs such as : paromomycin , quinoqurine hydrochloride (I ‘m not sure) Prevention is the same as entamoeba ; proper sewage disposal , good hygienic status , avoiding water from streams and contaminated sources >> in cases of stream water, to avoid the danger you can use a halogen tablet (chlorine tablet) you can put it in the water and wait for 10 min and then drink or simply boiling the water is enough . And whatever applies to the vegetables and fruits that are eaten raw and could be contaminated with animal fecal material, also, oral genital sex is a possible route of transmission where the cysts can be transmitted. But these organisms are mainly transmitted through water contamination *These organisms are usually seen with Cryptosporidium parvum
Cryptosporidium parvum Cryptosporidium is very common, (crypt- means hidden, -sporidium- spores; the hidden spore, intracellular inside the microvillus) Cryptosporidium is the smallest protozoa; it’s around 4 µm in diameter. There’s only one protozoal spp. that infect both human and animals which is; cryptosporidium parvum. Cryptosporidium parvum from the class called sporozoa, which is the same class of plasmodium malaria, falciparum, vivax, toxoplasma gondii (causes toxoplasmosis داء )المقوساتand ovale and we have others called isospora very close to the toxoplasma. Clinical presentation Cryptosporidium is the other protozoa that cause severe watery diarrhoea like Giardia lamblia. The difference is in clinical presentation we don’t see flatulence, or steatorrhea. They share malabsorption and severe watery diarrhoea. Epidemiology Cryptosporidium mainly affects the immune-compromised (diabetic patients, AIDS patients, patients taking cytotoxic drugs or chemotherapy) and because they are immune-compromised the prognosis of the disease will be catastrophic. In the 7
hospital we see almost 2 cases of cryptosporidium every week because we have leukemic patients on cytotoxic drugs that develop diarrhoea. So when leukemic patiets develop diarrhoea it’s cryptosporidium Until proven otherwise. *Slim disease: the diarrhoea that develops in AIDS patients, which is mainly caused by cryptosporidium parvum. Some children with watery diarrhoea are not immune-compromised but they get infected, here the duration of the disease will be shorter; it’s a self-limiting; There’s no need to treat these patients they recover on their own. Life cycle Have asexual phase and a sexual phase. In Malaria the asexual phase occurs in human and the sexual phase occurs in the anopheles mosquito. In cryptosporidium the asexual (called schizogony) and the sexual phase (called sporogony) both occur in the GI Tract of human as well as animals, While the toxoplasma sexual phase occurs in cats and the asexual phase occurs in human and pigs. Transmission In most of the cases The infection is transmitted from person to person (that’s why we should have the contact precautions or isolation) We could get it from water sources; could be food but mainly water. Autoinfection may occur if children or patients touch their perianal region then put their fingers in their mouth. Pathogenesis Patients ingest oocyte, which goes to the small intestine into the microvilli resulting in their destruction (malabsorption and diarrhoea). The oocyte contains 8 sporocysts which form the trophozoite, then they form type 1 merozoite then the cell will rupture, they go and infect other cells. Some of these trophozoites form type 2 merozoite; which are the male and female gametocytes which fuse to form a zygote (which is the oocyte). Then oocytes will be released in stool and contaminate others.
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Diagnosis acid fast stain “used for M.tuberculosis and cryptosporidium”, we see the oocyte; red in colour and so many in number (200000 per 1 gram of stool) In stool tests we look for both cryptosporidium and giardia and you should know the differences between them. immunofluorescence techniques; adding flourescenated antibodies to the stool specimen, then we have positive control and negative control to compare, but it’s more expensive ELISA to detect the antigen in the fecal material and the antigens of E.histolytica and Giardia Treatment: water and electrolyte replacement if the patient is immuncompetent usually it’s self-limiting, If he’s immune-compromised the paromomycin is given. And improving the immune status help as well Prevention: the same as the Giardia ; contact precaution and using gloves , boiling water, but here the regular water chlorination(half part per million ) is not enough we may need three parts per million to get rid of them
We have another protozoa, we call it Balantidium coli; maybe you have to read it on your own, it is the largest protozoa, it's present in pigs, one of the ciliates ( like paramecium) and it causes gastroenteritis where the cysts contains 2 nuclei ; micro and macro nuclei; it has the trophozite as well as the cystic form. And those usually come from pigs, they contaminate our fruits and vegetables, and when we eat that we could develop gastroenteritis so we diagnose it simply by looking at the microand macro-nucleus. The macronucleus looks like kidney, and simply the treatment/prevention is just like those of entamaeba histolytica.
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Worms In the GIT we could have so many diseases caused worms, and these worms could be very small, maybe up to 4 mm in length, and others can be up to 5-10 meters in length. Classified based on their shape: roundworms: (you are going to see many of these in your clinical practice),they can be pin worms like Enterobius Vermicularis , whip worm; (because it looks like a whip) trichuris trichiura that used to be called oxyuris or the typical round Ascaris lambricoidis ( ;)االسكارسwhich looks like the earth worm ()دودة االرض.also, hook worms ()الديدان العكفية: like ancylostoma duodenale, keytar americanus. And the last one strongyloides stercoralis which causes a disease called strongyloidiasis . and we have one that we call it trichenalla spiralis which is the smallest causes adisease called trichinosis; we diagnose it by seeing the larva inside the muscle fibers after muscle biopsy). **You should know the life cycle of all these worms, because if you understand how is the life cycle of these worms you can interfere with these life cycles and you can stop it.>> if you want to memorize the table , it’s found on page 836 table 53-2 in Sherris Ways of transmission Mouth :Some can be transmitted through the ingestion of eggs, like Enterobius Vermicularis, trichuris trichiura ,Ascaris lambricoidis. But these eggs have to be embryonated, which means that they have to mature outside the human body then we get infected by eating them Skin :While the others like strongyloides stercoralis and Necator americanus , the infection is by penetration through the skin, the infectious stage is called the filariform larvae which penetrates through the skin and continues the life cycle inside. Here we should know where to look for these eggs; some in the stool, some in the perinanal region, or to look for the filariform larvi in the stool, or in the mud. Some do have what we call a free life cycle, which means a free living style, they can grow on their own, males, females and so on (inside the human body or in the mud) for example strongyloides stercoralis. So these will have higher infectivity because they survive in the mud and have an extra source of replication, extra source of these filariform larvae
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The end I did my best to make it as organized as possible Sorry for any mistakes
Thanks for everyone who helped me doing this lecture :) Be a Rainbow today and Everyday :D
Aya Al Nobani
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53/59 7/9 25
Microbiology Intestinal infections with parasites I Ziad Al-Nasser Bayan Abu Khalil Tuesday, 22/11/2011
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Microbiology lecture 7 Tuesday, 22-11-2011 Done By: Bayan Abu Khalil You will find a superscripted number above some new terms, then refer to the last page where the clarifications from Wikipedia are found.
The worms that we will cover in GIS include : o Nematodes or Nematoda : the roundworms. o Cestoda or Cestodes : tapeworms. o Trematodes or flukes : such as Schistosoma.
We can identify the worm by its egg’s shape, and some by the larva so it would be the diagnostic stage.
So it’s important to know the relation between these worms and the clinical presentation. The clinical presentation could be related to the presence of worm inside the GI tact, to the passage of the worm to the body; like the eosinophilic granuloma, or could be related to entrapment of eggs as well as schistosomes.
Humans can act as definitive host (where the sexual cycle of the worm is taking place) or as an intermediate host. And remember that humans act as death intermediate host; nobody eats human! So the life cycle will stop.
In this lecture we will discuss types of roundworms ,,,
Enterobius vermicularis Is a pinworm; type of roundworm class. Infects children usually. Anal itching is the main problem associating with; specially during the night Small one; the female is up to 1 cm in length and the male is usually shorter. Females are mostly larger; they have to engorge or hold eggs.
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Typical nematodes; have mouth, esophagus, uterus of eggs and anal orifice, so have simple alimentary tract. We can use the tail for identification, but not for this worm. The eggs look like the letter of D; D-shape . They are (the eggs) very sticky so usually you see 2, 3 ones adherent to each other. The infectious stage: Embryonated eggs (Eggs have to be embryonated ) Mode of Transmission : Feces. * But you can’t use feces for diagnostic purposes *; just to know! Life Cycle: Males and females of enterobius vermicularis habitat the cecum. Then when the female gets pregnant, she can’t lay down her eggs inside the intestine; the milieu البيئةor the environment inside the intestine isn’t suitable. Then she leaves the cecum, go through ascending colon>> transverse colon>> descending colon>> sigmoid colon>> rectum then to the anal orifice where she leaves through. It does that during the night; that’s why the severe anal itching takes place during the night. Then she gets out of anal orifice, lays down her eggs at the prianal region, and then gets back. So she gets back and forth. So imagine a child with this back and forth worm, he starts itching the anal orifice and he might get superinfection bacteria. Then after itching, he puts his finger in his mouth so re-infects himself again. Or puts his fingers in his mother or sisters, so the whole family might start itching as well :s Sometimes when the female is getting out of anal orifice, she may go into the vagina; by mistake , so that may associated with severe infection. Or she may go to the urinary bladder.
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* Severe anal itching during night = enterobius vermicularis , until proven otherwise * Prognosis :
Clear clinical manifestation : Pruritus ani1
Seeing the eggs; How ?? By using Graham’s Scotch Tape Technique ( but I’m not sure about this , though I looked for it in the net ) You get a thumb depressive, then put the sticky tape in an inverted form (the sticky part exposed) then open the anal orifice in a way, then touch the perianal region of the child. Then take the tape>> put it on a slide>> look it under microscope>> no strains ,then there is nothing. Under microscope you can see the flattened part, the curved part (D-shaped), and the embryo sometimes. Eggs are around 30 µm in length by around 15 µm in diameter.
If you do stool analysis, it would be negative. Sometimes you could see the adult worms which are whitish-greenish in color.
Treatment : DOC : Mebendazole; Vermox is the commercial name. and there are other drugs of this group; like : Albendazole and Tinidazole. Mebendazole should clear all the worms from the infected child. You can use purgatives (as a laxative agents; )مُليّناتas well to clear these worms as well.
Prevention: 1. If the child is infected, he has to be treated as well as the whole family. 2. Linens should be boiled; they might be contaminated from the child’s underwear. 3. Sometimes when the mother is tidying up the bed, these eggs could fly in air so they would be inhaled! They could stick in the throat so she swallows them and she becomes infected. *So ALL things around have to be cleaned* and * The most important thing is to treat the source of infection * 4
Trichuris trichiura A whipworm; of a roundworm class. Looks like a whip.This is the anterior end which is a spear-like in shape ()رمح, and the worm uses it to attach to the colon. You can see the uterus and ovaries. Females are larger; 4.5 cm in length. Habitat colon Epidemiology: Not present in our part of the world, it’s usually in the temperate areas or in the hot weather in general. Concentrated in areas with indiscriminate defecation, improper hygienic and sanitary conditions.
Life Cycle: Males and females inhabit the colon. They copulate then the female get pregnant with eggs. Eggs are the pathognomonic and are typical in shape; they look like a lemon in shape. Eggs have bipolar prominences. They come out through stool. And if the patient has indiscriminate defecation then the field would be contaminated with many of those eggs. Children playing in the mud, sand and so on, then eat mud ( a psychological problem called * geophagia *) , so they eat embryonated eggs so they get infected. Or eggs could contaminate fruits, vegetables, cucumber, lettuce, and salad components, so we would be infected if we have no proper hygienic practices. These embryonated eggs go through stomach, small intestine, large intestine where the eggs will hatch and the embryo comes out. Males and females grow up and start a new life cycle again.
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Clinical problems related to presence of these worms in the intestine : 1. Iron deficiency anemia 2. Rectal prolapse 3. Very minor eosinophilia due to presence of these worms attached to mucosa.
We don’t see Eosinophilia in Enterobius vermicularis, because this is perianal itching and no damage to the intestine.
** This one (whipworm) could induce more damage than the pinworm; HOW?? This whipworm attaches itself to the large colon through the spear part. So it depend on how many worms are hanged there; each one of those causes blood loss of 0.005 ml/day (0.005 ml/worm/day) So if this blood has not been compensated, then the patient is going to have iron deficiency anemia. And if blood is compensated, so the patient will be asymptomatic. ** No specific signs and symptoms related to presence of these worms in intestine. May be there would be abdominal pain, diarrhea, constipation or cramps. They found something specific of those. Imagine10 or 20 are hanged to the mucosa of large colon, the rectum or the anal orifice. Now when the patient is defecating, he’s going to have what we call *Shearing Force* . It means that these worms will pull the mucosal lining outside, so the patient will get * Rectal prolapse2 * . Diagnosis : Stool analysis; looking for their eggs. You can see the bipolar prominences, the lemon shape and a thick shell. Eggs are 50 µm in length by 30 µm in diameter. Treatment : DOC : Mebendazole (Vermox) It interferes with protein synthesis of the worms so they relapses and get out of the body. Purgatives 6
Ascaris lumbricoides Look at the picture, and identify its parts. It has lips for attachment , but they don’t cause any harm due to its attachment . Females are longer, they are 30-35 cm in length. Whitish- greenish in color. Very similar to the earthworm. Males and females are present in small intestine, large colon and the whole alimentary tract. They produce more than 200,000 eggs/ worm/ day! Typical eggs can be seen in stool analysis, as well as other worms. Eggs are spherical in shape, and have thick mamillated albuminous layer When immature eggs become fertile, the shape of them will be different. Then they may hold embryos that have to mature outside human body to be infectious. ** Differences : in pinworms : auto infection immediately. in Trichuris trichiura : eggs have to be mature,, no auto infection. in Ascaris lumbricoides : same as Trichuris trichiura. And here in the last two worms,, maturity associated with a worm climate.
Life Cycle: Eggs produced in intestine are getting out through the indiscriminate defecation. People defecate in fields or throw the sewage into the fields as fertilizer!! So the area will be contaminated with these eggs which will be mature there. And then fruits and vegetables would be contaminated with these mature eggs, then one who eats those,, eggs will go to the intestine. Now the life cycle here is different,, HOW?? The eggs hatch up ( يفقسthe embryo comes out) and the embryo leaves through the portal circulation and systemic circulation, then ends in the lungs. 7
They can’t pass through pulmonary arteries into the arterial circulation and continue,, so they pass through the alveolar membrane into the alveoli. Then they coughed out into the throat, then swallowed into intestine where they copulate and the life cycle starts again. Very important to know: Here clinical maniestations are related to the passage of these larva to the lungs; where massive eosinophilia is going to take place. Sometimes, patients may develop pneumonia, and when you make a culture, it will be negative, and this is * eosinophilic granuloma * or *Löffler's syndrome3 *. Löffler's syndrome is a pneumonia due to massive eosinophilia due passage of these larva into the lungs.
Clinical manifestations : Mainly, No specific symptoms 1. The patient may be asymptomatic, although it might be hundreds of eggs inside his body. They compete with nutrients but if the patient is fed well he would have no signs and symptoms. But if the patient isn’t fed well, there will be weakness and weight loss. 2. Worm Ball; it depends on how many eggs are in the body. This worm ball may block the intestine so causes *intestinal obstruction* 3. Acute pancreatitis; the serious one. They could block the ampulla of vater , so all pancreatic secretions will be blocked and cause acute pancreatitis. And this one of the emergencies in medicine. 4. Some will go back to stomach, then with vomiting they come back to the mouth or to the nose. Diagnosis: Stool analysis in which you see hundreds of eggs with mamillated albuminous layer, mature and semicircular in shape. They’re around 55 µm by 60 µm in diameter. 8
Most are seen with light power of microscope, so they’re easily seen at the power of 10x and 40x. Treatment : Mebendazole and albendazole. ALL the roundworms have the same DOC which is Menedazole. Prevention : Educate the public how this worm is transmitted. Never use excrement of human body as fertilizer. Proper sewage disposal system. Proper sanitary condition. Proper use of the toilet and handswashing. Washing of fruits and vegetables. Children shouldn’t be encouraged to play in the mud.
Ascaris –like worms in animals o Animals have Ascaris –like worms; which are called * Toxocara * : Toxocara canis : for dogs Toxocara cati : for cats o They have the same life cycle as those for humans. o Their eggs look like those of Ascaris lumbricoides but smaller. o Can the adult worms develop in our body ? NO. o What will happen if somebody ingests eggs of Toxocara canis or Toxocara cati? When we ingest eggs, they go to intestine, then hatch up , then the larva will pass through portal circulation, venous then go to the lung. Their size is so small , so they won’t pass through the alveolar membrane into the lungs. Instead, they pass through pulmonary artery into the systemic circulation. Then the arterial blood takes them to anywhere in our body. Now imagine if one of these eggs is lodged (ended up) to the CNS or the eye or other tissue,, what will happen?! This is what we call * Visceral Larva Migrans*. 9
And this is very important; because ophthalmologist while testing a tumor in the eye, he ends up that this is a larva of toxocara canis ,, so those patient will complain of massive eosinophilia that gives you an indication that this is a larva of worm . So if you want to keep dogs or cats, you have to worm them ; *Worming *. You have to treat them from worms, otherwise they can be health hazard to us. In Europe and US , the owner of the dog or cat is responsible for the disposal of excrement of his dog or cat! “They use the same medication to treat animals; cats and dogs”; any one develops a visceral larva migrans, then you have to use albendazole to get rid of the larva . Also you need anti-inflammatory drugs and sometimes you may need steroids to alleviate severe inflammatory reactions that may occur.
Hookworms : الديدان العكفية Two species infect humans : 1. Ancylostoma duodenale; is in the old world. 2. Necator americanus ; is in the new world like Americas Both have the same shape and life cycle. They differ only in the shape of their mouth. Ancylostoma duodenale has 4 pairs of teeth, while Necator americanus has cutting plates شفرات. They use those to bind to the intestine. They are pinkish in color, look like the letter of S; S-shaped or the hook. Males have usually a whip-like thing at the end of the tail called *copulatory bursa*; used for copulation with females. While females have a uterus to engorge the eggs. Patient may have 10-12 pairs of these worms in his intestine. 10
Eggs are oval in shape, and have embryo inside in many different levels of development like a plastomere and so on. And there is an invagination and a clear area around the egg’s wall. They are 60 µm by 30 µm in length.
Life Cycle : Males and females copulate in the small intestine, then females put large numbers of eggs. These eggs produce larvae called * rhabditiform larvae * outside the body. Sometimes they may be seen inside. These eggs go out through indiscriminate defecation to the fields and so on. They hatch outside the human body when environmental conditions are appropriate like a worm climate. Larvae come from these eggs called * rhabditiform larvae * whcih swim in the mud, fields and so on. They are 100 µm in length. Then they grow up (after doubling in size; 200 µm in diameter) to become filariform larvae; which is the infectious stage. And also they swim in the mud. So when a person walks barefooted ًحافيا, they penetrate through the skin; usually through the wipes between the toes. Then go to venous circulation , then to the lungs but can’t continue like the Ascaris. So they go through the alveolar membrane into the alveoli, then they are coughed up into the mouth then swallowed into the intestine. In intestine, they develop into males and females and a new life cycle starts again.
Clinical Presentation : Lung manifestations as well as with Ascaris. And massive eosinophilia due to larvae circulating in our body. Skin itching related to passage of filariform larva into the skin. Loosing of blood in the site of attachment to the intestine (by the teeth or the cutting plate). Ancylostoma duodenale causes loss of 0.12 ml/worm/ day. while Necator americanus causes loss if 0.03 ml/ worm/ day. 11
And it depends on how many worms are there,, so causing iron deficiency anemia; just like those of Trichuris trichiura.
In animals : They have one similar to those of humans which is “Ancylostoma braziliense”; the hookworm of cats (though the Dr, said “the hookworm of dogs”, but it’s of cats as written in wiki ). If the cat is walking near a beach or swimming pool, they excrete eggs which hatch in the beach, rhabditiform larvae will develop then filariform larva. Then they may penetrate the skin of one laying on the beach. But they discover that they have infected the wrong host! , so they can’t continue their life cycle in humans, so they keep walking under the skin causing severe inflammatory reaction . It’s a creeping eruption called *cutaneous larva migrans*. They are hanged to the skin causing severe inflammatory reaction in the skin which is treated by anti-inflammatory ointment or lotions. So remember that when keeping dogs or cats, they must be wormed (treated) with Mebendazole and Niclosamide.
Strongyloides Stercoralis Causes a disease called strongyloidiasis. Common in South East Asia, Vietnam, Cambodia and so on. Very small; 2-3 mm in length. Cylinder in shape, have alimentary canal and uterus where they have eggs in ova. The interesting thing here is that eggs can’t be seen, because immediately when eggs produced they hatch and larva will come out. You see rhabditiform larvae ,then filariform larva. 12
These worms infest themselves underneath the mucosal lining of the small intestine. Rhabditiform larva comes out from eggs in the stool as well as filariform larva. When patient defecates outside, we see 3 scenarios of these types of infections and so they are a successful pathogens : ( I wrote what the Dr. said, then copied what’s written in Sherris book regarding the 3 scenarios . You find it in the end of page 14) First scenario : The same as the hookworms; filariform larva is outside the body in the mud,, patients walking barefooted , worms penetrate to the skin, then through venous circulation to the lungs,, alveoli,, cough and swallow to intestine. Second scenario : Filariform larvae don’t continue outside. They could penetrate to the skin, then continue the life cycle. This is called *Autoinfection* as the pinworms; that when we talked about how children put his fingers in his mouth so reinfect himself. Third scenario : Is what’s called * Free-Living cycle* here filariform larva will mature and turn into adult males and females. They copulate outside the human body, then produce rhabditiform then filariform larvae. Then if somebody walk barefooted, they penetrate into the skin and continue the life cycle to the intestine.
Clinical manifestations : Severe abdominal pain and diarrhea due to presence of these worms in the mucosal lining of intestine. Bacterial infection; like salmonella, in the area where the worm penetrate through the skin. Eosinophilic granuloma, due to passage through the lungs.
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Diagnosis : Usually the rhabditiform larva can be seen in the stool We don’t see eggs; very important to remember. We see eosinophilia We have to learn how to differentiate between the rhabditiform of the hookworms from that of Strongyloides stercoralis. Rhabditiform of Strongyloides stercoralis has short buccal cavity while that of hookworm has long buccal cavity. And we can differentiate that by the location of genital primordium. Treatment : DOC : Thiabendazole, and albendazole. Prevention : Prevent indiscriminate defecation Education Not to walk barefooted.
What’s from Sherris : Three different life cycles have been described for this nematode. The first, or direct cycle,is similar to that observed with the hookworms. After rhabditiform larvae are passed in the stool, they molt on soil to become filariform larvae. Filariform larvae can penetrate human skin. After transport to the lung in the vascular system, they are coughed up, swallowed and then mature to adults in the small bowel. In the second, or autoinfective cycle, the rhabditiform larva’s passage through the colon to the outside world is delayed by constipation or other factors, allowing it to transform into an infective filariform larva while still within the body of its host. This larva may then invade the internal mucosa (internal autoinfection) or perianal skin (external autoinfection) without an intervening soil phase. Thus, S. stercoralis, unlike any of the other intestinal nematodes, has the capacity to multiply within the body of the host. The worm burden may increase dramatically, and the infection persist indefinitely, without the need for reinfection from the environment, oftenwith dire consequence to the host. In the third, or free-living cycle, the rhabditiform larvae, after passage in the stool and deposition on the soil, develop into free-living adult males and females. These adults may propagate through several generations of free-living worms before infective filariform larvae are again produced. This cycle creates a soil reservoir that may persist even without continued deposition of feces. 14
1
Pruritus ani :
(also known as anusitis or "the swamps") is the irritation of the skin at the exit of the rectum, known as the anus, causing the desire to scratch. 2
Rectal prolapse:
normally describes a medical condition wherein the walls of the rectum protrude through the anus and hence become visible outside the body. 3
LĂśffler's syndrome :
or Loeffler's syndrome is a disease in which eosinophils accumulates in the lung in response to a parasitic infection
*
Eosinophilic pneumonia (EP)
is a disease in which a certain type of white blood cell called an eosinophil accumulates in the lung. 4Deworming:
(sometimes known as worming or drenching) is the giving of an anthelmintic drug (a wormer, dewormer, or drench) to an animal to rid it of intestinal parasites, such as roundworm and tapeworm.
THE END ď &#x160; Forgive me for any mistake
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Microbiology Tapeworms Ziad Al-Nasser Yousef Odeibat Wednesday, 23/11/2011 24/10/2011
Tapeworms General Structure and Morphology: They look like a tape, they are whitish and thin. They are hermaphrodite, male and female genital organs are in the same organism, we don’t have male worm and female worm. They are composed of three parts: 1- Scolex (pl. Scolices): it is the head which is the most important, and the primitive we call it protoscoleses. Scolices are armed, that means they have rostellum (pl. rostella) and hooklets which can use them to attach to the intestines, or unarmed. Suckers are found in both types that are used to attach to the intestine. 2- Neck. 3- Strobila: the tape of the worm and it is formed of so many segments each segment is called proglottid, and the ones that are coming out of the neck we call them immature, in the middle are called mature, and the in last part we call the gravid (means pregnant). In garvid proglottids we have genital pores, and uterus and branches of uterus, ovaries and you can see the eggs and the eggs inside we call them hexacanth embryonated eggs because we have six hookelts here and the shell is double striated. hexacanth embryonated egg they look the same in Taenia solium and Taenia saginata.
Taenia saginata Structure: Or called beef tapeworm, and each one of those worms we call it by the name of the animal that is responsible for their infection in humans, and the beef tapeworm we get infected with the adult worm by eating raw. So because Taenia solium infects pigs it’s called pig tapeworm.
The scolex it unarmed and have four sucker, a neck and Strobilia. They have also auto-execratory system on both sides. They don’t have any vascular system. They absorb nutrients from the cuticle (outer skeleton of the worm). They have 5000 – 10000 of proglottis. proglottids have genital pores and vagina. so the sperms that develop go to the vagina of the same proglottid, and eggs get fertilized in the vagina, or can go from one proglottis to another proglottis. And these genital pores they could be alternating and in other worm they could be on the same side. the number of branches of the uterus we use it for differentiation in Taenia saginata you can get up to 15 - 30 branches while in the Taenia solium (tapeworm of pigs) it is much less. Taenia saginata length can reach up to 10 meters while Taenia solium maybe up to 5 meters in length.
The Life Cycle: 1- The worm is attached to the patient’s the patient small intestine by the head is and pieces of the strobilia could be detached and leave through the stools and when it leaves through the anal orifice some of these eggs could be squeezed outside and they could contaminate the perianal region or the whole proglottid can be expelled outside. 2- If the patient has indiscriminate defecation in the fields these eggs are going to contaminate most of the grass and everywhere in the environment. 3- cows come and eat the grass that is contaminated with hexacanth embryonated eggs so these eggs will go to the GIT of the cow and hatch and the embryo comes out and then it goes through the intestine into the portal circulation and venous circulation then the pulmonary artery into the systemic circulation and the form a cyst in the muscle of the cow and these cysts are called Cysticercus bovis (Cysticercus means a primitive cyst that has protoscoleses). veterinarian could see these cysts by simple inspections of the meat, they have sleazy thick type of yellowish discharge dots on the surface of the meat so if humans eat the beef whether raw or ground stake-like then they eat the Cysticercus and they go to the intestine where the Cysticercus open up and protoscolices come out and they attach to the intestine and strobilia start to develop out of the scolex and then it grows up and the cycle will keep going on as such.
Humans are the only animal that can act as a definitive host “primary host” means if humans eat eggs of Taenia saginata nothing is going to happen, humans cannot act as intermediate host.
Complications: The consequences of teniasis saginata is very minimal The problem is simply the presence of very large worm, and usually its one worm with a length about 10 meters more that 5000 proglottids in the intestine. So it depends as I said before on the nutritional status of the patient, if nutrition are compensated they are usually asymptomatic, maybe sometimes pain and diarrhea. We don’t see any complications like the other worms. it has been reported that the only symptom is that patients see this worm when they defecate, and these worms can cause embarrassment for the person sometime; for example someone is giving a speech and a 2 meters worm comes out of his anal orifice to his pants and the floor!!
Diagnosis: By stool analysis to look for the hexacanth embryonated eggs wish is around 40 – 50 micrometer in diameter. Graham’s scotch tape technique because when the proglottid is squeezed out of the anal orifice the eggs will come out and contaminate the perianal region so you can use scotch tape and look for the hexacanth embryonated eggs, by this you can isolate 80% more yield than doing stool analysis. You can stain proglottids by congo red stain and you can see the branches around 30 branches and you can see the genital pores and sometimes the scolex if it hat has been detached completely
Epidemiology: People get infected by eating raw beef. Many people eat raw stack or medium raw, there are different ways to cook stack. Or the Lebanese dish that is very common in our part of the world where we have Al-Kebeh Al-Nieh ( )الكبة النيةand it is mentioned in parasitology books.
Treatment: The drug of choice that we use is Niclosamide (commercial name: Niclocide) and we can use Praziquantel also. The pumpkin seeds you can boil it and drink it they are very effective then you take a purgative it should be washed.
Taenia solium Infect pigs mainly. Cause teniasis solium. The main difference between those species and tenia saginata that humans can act as intermediate hosts here so they act as pigs!. Structure: They have Scolices which are armed; have rostellum, and they have four suckers. The proglottids are shorter, one worm has around 1000 – 2000 proglottids. Uterus branches are shorter. Usually one worm and it is present in the small intestine. 2 – 3 meters in length. The eggs pass through proglottids, the rapid ones they pass through the anal orifice outside in the feces. (me too!! I didn’t get what he wants to say!).
The Life Cycle: 1- Indiscriminate deification contaminating grass and fruit. 2- Then pigs come and eats these contaminated grass and fruits that are contaminated with hexacanth embryonated eggs. They will go to the GI tract of the pig and the embryo comes out and they go through the portal circulation the venous blood then arterial blood to the different muscles and tissues and they form a cyst called Cysticercus cellulosae and the presence of these Cysticerci all over called Cysticercosis. 3- So they are present in the meat or the muscles of the pig, pork, so people who eat pork they can eat the Cysticercus cellulosae and they go to the
intestines of human they have protoscolices they come out and the adult worm comes in the intestine of the humans to cause teniasis solium. But if humans ingest the eggs, because humans can act here as intermediate hosts as we said and humans genetically are much closer to pigs than cows, so this is in comparison with Taenia saginata where they cannot act as an intermediate host, so the eggs go to our intestine they hatch and the same thing, larevae will circulate in the body and ends up to wherever the circulation takes them some in the brain, eye, the muscles and they form many cysts here and each one is called Cysticercus cellulosae and this conditions in humans we call it cysticercosis and it can occur in teniasis solium but not in teniasis saginata.
Epidemiology: In Europe and USA people eat pork and make sandwiches of it, they eat it smoked and it’s very popular there because the fibers of the pig’s meat is short and easily can be digested, and the fat of the pigs is very close almost similar to that of humans and rarely precipitated in the blood vessels and so on so it’s very popular there. Here we don’t talk about religious believes this not our business is but we give you scientific facts! Some Muslims can be infected by this worm in USA and Europe, because when they grinned the pork in the grinding machine if that pork is infected it could contaminate the grinding machine and usually they don’t clean them and afterward they maybe will grind the beef so the beef could be contaminated with that of pork and we could be infected and that happens!
Diagnosis: By looking into the hexacanth embryonated eggs. Staining of the proglottids to see the number of branches, they are less shorter and sometimes we can see the armed head. In cysticercosis: o the presence of Cysticercus cellulosae in different tissues we can make the diagnosis by imaging technique like MRI where we can scan the brain and eye and some of them may look calcified. o By serological technique using antibodies against the antigen of Cysticercus, massive eosinophelia.
Treatment: Like taenia saginata we use the Niclosamide and Praziquantel either one of them or the Albendazole. We can use those for cysticercosis although the treatment is so difficult in those cases and sometimes we could end up in surgery like space-occupying lesions wherever those are located.
Prevention of teniasis saginata and teniasis solium: First of all it’s extremely difficult to change the habits of people you cannot go to a Lebanese and convince him to stop eating Kebeh Naya! It’s impossible. So at least we have to inspect the meat in slaughterhouses and usually they hire vets and they inspect the meat. And what you feed those animals is what you get so if you control what they eat then they are safe this is very important and for cysticercosis where we act as intermediate. We need to wash vegetables and fruits and anything that we eat otherwise they could be infected this is important
Hymenolepis nana Humans can act as primary and intermediate host in the same time. Associated with abdominal pain diarrheas. In children more than adults.
Echinococus granulsus and Echinococcus multilocularis or the hydatid worm Structure: They are very common in our part of the world and we talked about it in the respiratory.
They are responsible for what we call hydatid disease or hydatid cyst. It has armed scolex and then 3 segments: immature, mature and gravid. It is around .5 cm -1 cm in length so it’s small. The habitants of this worm is canines which includes dogs, hyaena, foxes, wolves and so on. Humans cannot act as definitive host so these worms are never isolated from human’s intestines.
Life Cycle: The life cycle of this worm goes between dogs and their prays usually sheep goats and herbivore.
1-
The worm is present in the intestine of the dog, and then produces eggs (hexacanth embryonated eggs as the others) which are excreted by dogs outside ( by nature, dogs excrete their fecal material wherever they go).
2- So these eggs will contaminate the grass, vegetables, fruits & so on.
3- If the herbivores came and eat these eggs which are contaminating the vegetables & fruits, then they go to the intestine of the sheep – let’s say- then they end up in the liver ( first filter in the body) via the portal circulation, where they form cyst called hydatid Cyst in the liver.
4- Or they could pass from the first filter to the second filter which is the lungs. So they end up either in the lungs or the liver forming hydatid cyst or if they pass from the second filter (lungs) then they can disseminate anywhere in the sheep’s body.
5- Usually, in sheep, they end up in the liver. in Europe & the United states, they don’t eat the internal organs like the liver, instead they through it to
dogs. When dogs eat the hydatid cyst located in the liver, and this hydatid cyst has a double wall, a hydatid fluid, and they have a protoscolices inside, which is the primitive head, so the dog eats that, and each one of these heads will develop the adult worm in the intestine of the dog. So you can see, sheep can’t act as definitive hosts, i.e. the adult worms can’t develop in sheep, or herbivores. Humans are similar to sheep, so if they eat grass, vegetables, fruit and so on, they will develop hydatid cysts , either in the liver, in the lungs, or anywhere in the body. And these cysts may increase in size between 0.5-1 cm per year. So imagine having 5, 3 or maybe 1 of these cysts enlarging continuously in the liver, or in the lungs forming space – occupying lesions. Some of the complications of these cysts is that they may rupture. The patient is usually sensitized and he could go into anaphylactic shock, and if the patient survives, then any of these protoscoleses that develop, could develop into another cyst, they cannot develop into a fully sexually mature adult worm inside humans, because the human body is not a suitable physiological environment for this development. And if it ruptured in the lungs you can also cough the protoscoleces outside.
Diagnosis: Hydatid cysts usually end up with a space - occupying lesion, and you discover that with imaging techniques (X-rays). And you see it as welldemarcated lesion. Sometimes we can serologically also determine the antigen of the worm or antibodies. Microhemagglutination; where you get the antigen of the worm and stick it to the RBCs and then get the serum of the patient and then you’ll have agglutination simply. Making the diagnosis by aspiration is contraindicated because any leak of the fluid could lead to anaphylactic shock, but it’s sometimes done under Xray guidance.
Treatment: 1- PAIR technique, In the presence of good imaging department under Xray guidance you can inject formalin or ethanol inside the cyst, then aspirate and then inject and then re-aspirate. This is being done for 3-4 times until it becomes sterile. The process of aspiration and re-aspiration is called PAIR; Puncture Aspiration Injection Re-aspiration. If we take the aspirated fluid and look at it under the microscope; we can see the protoscoleces. There are many hydrated cysts in the abdomen depending on the number of the eggs ingested. These are the protoscoleces and you can see the primitive egg of the worm (hexacanth eggs and the hooklets) which are inside the hydatid fluid and they are called hydatid sand. 2- if it’s not possible to do PAIR then we do open surgery; they open, take the cyst out, aspirate, re-aspirate, sterilize by formalin or ethanol, then they open it up and take the germinal layer which is the inner layer. The germinal layer contains a sac and a protoscoleces out. This is done when the cyst is in a sensitive area other than the liver or the lungs. In Echinococcus multilocularis the cysts develop in multi-loci, they expand laterally causing large damage to the tissue. They are divided into 1)Pastoral; means domestic and 2)selvatic; means wild, which is usually in the jungle. So if someone ate vegetables from the forest he could develop infection of hydatid cyst. And they occur in children more than adults.
Prevention: Proper washing of vegetables.
Dogs have to be clear out of these worms otherwise these dogs could cause infection to humans.
Diphyllobothrium latum (fish tapeworm) Structure: It has scolex, neck and strobilia; which has 2 grooves one to the left and the other to the right; these grooves are called bothrium,. The proglottids have longer transverse section than longituidinal one. The genital pores are on the ventral side. The eggs are operculated eggs; they have a cover called operculum. The emberyo inside the egg is called coracidium, and these eggs have knobs. They can be 60-70 microns in length. Those worms are located in the terminal ileum. They can be very long; about 10 meters in length. There may be about 10000 proglottids and just one worm. Present mainly in Scandinavian countries; Russia or Finland because they eat raw fish.
Life cycle: Worms in the terminal ileum, produce eggs Indiscriminate defecation or by throwing human excretions in fresh water, eggs go into the water, the coracidium comes out of the egg and swims in the water using it’s cilia, water flea or Cyclops eat the coracidium Inside the body of the Cyclops the procercoid develops, fish eat the cyclop (which now contains the procercoid).
In the body of the fish it develops into plerocercoid; usually in the flesh of the fish. If the raw fish is eaten the plerocercoid will go to the intestine, the plerocercoid starts to grow up into the adult worm (hermaphrodite), go to the terminal ileum and the scolex starts to bind and then the proglottid starts to develop.
Diphyllobothrium latum and B12: The Diphyllobothrium latum has a very strong preponderance to absorb vitamin B12, most of the vitamin B12 that the patient eats, can be absorbed by this worm. This will lead to vitamin B12 deficiency, which in turn lead to megaloblastic anemia because vitamin B12 is involved in the DNA synthesis. Also, vitamin B12 is important for the function of the brain so its deficiency will lead to mood changes , loss of sensation, parastesia, and other CNS symptoms. The anemia caused by this worm is NOT pernicious anemia , pernicious anemia is an autoimmune disorder caused by the deficiency of intrinsic factor that is needed for the absorption of vitamin B12 so if we measured the level of vitamin B12 in these patients , it will be low
Diagnosis: By doing a stool analysis and look for the operculated eggs of Diphyllobothrium latum
Treatment: is the same ;Praziquantel, nuclosamide
Prevention: in some countries(Scandinavian countries) they eat fish pickles (small pickled raw fishes) , so we can educate this people about the life cycle of this worm
and how it circulate around in the area, so that they wouldn’t throw human feces in the water , to stop the life cycle of these worms . And educate them about the importance of cooking fish before eating it. Sometimes we can kill these worms by freezing the fishes to -15 degrees for a week and it can kill the plerocercoid.
What About the other worms , the flukes , we talked about the schistosoma , you remember that have separate sexes . but we have others we have the paragonimus westermani which we studied in the RS, also clonorchissinensis infect the liver, main location is in the biliary tract, which is about 1.5-2 cm in length , the eggs of these worms are urn–shaped )) مثل دلة القهوة, they have a prominent shoulder and a posterior knob, they are hermaphrodites, having both male and female organs. and it’s lancet shape. They go from the bile duct into the intestine and they are excreted outside , if they reach the water they would contaminate it , the larvae inside is called mericidium (like that of the schistosome) and then the mericidium is eaten by the water snail, many different stages will develop ; Redia 1 Redia 2, sporocyst and cercaria , the cercaria will swim and infect the fresh water fishes and changes into another stage , we call it metacercaria (not present in schistosome) so the if we eat raw infected fishes ( which is very common in Japan and China , that’s why it’s called the Chinese liver fluke* , and it’s very common in China ) so people will eat the meta cercaria (and develop into an adult warm in the intestine of the human Complications : sever biliary obstruction , jaundice , cancer could develop due to the chronic irritation in the intestine Diagnosis : by stool analysis and look for the urn- shaped eggs Another worm is called Fasciola hepatica(also called the sheep liver flukes) the only difference is that the cercaria end up in the watercress ( )االعشاب المائية
where they change into metacercaria , then these watercress might be eaten by some people , and they will develop the disease in the liver , thay have large operculatedeggs like these of the Diphyllobothrium latum. Another one is called Fasciolopsis Buski. Only present in the intestine , it’s a big one up to 7.5cm and the life cycle of those , is that the metacercaria ends up in the water chestnuts (it’s used in China) , so it goes to the intestine and grow into the adult worm and they have a lot of secretion that cause irritation to the GI tract , diarrhea and sometimes generalized edema treatment is the same for all of them ;Praziquantel (more common), nuclosamide, also ,we could be using the albendazole Another one which is very common in our area Heterophyes heterophyes, its metacercaria also infect the fishes (فسيخ, salted fishes that has a very bad smell when cooked ,common in egypt ) , so the worms will develop in the intestine , this is the smallest one around 2 mm in length So many of them will infest the intestine so that diarrhea will develop , gastroenteritis diagnosis is done by stool analysis and finding the eggs which are very specific for the Heterophyes heterophyes Treatment is the same for all of them You should know the infectious stage for each one and where they are located and how to prevent the infection.
THE END