Graphic handbook of immunology and bovine infectious diseases by Grupo Asís

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GRAPHIC HANDBOOK

IMMUNOLOGY and INFECTIOUS DISEASES in cattle

Ana Doménech Gómez • María del Mar Blanco Gutiérrez • María Dolores Cid Vázquez María Teresa Cutuli de Simón • Alberto A. Díez Guerrier • Gustavo Domínguez Bernal Alicia Gibello Prieto • Esperanza Gómez-Lucía Duato

IMMUNOLOGY and INFECTIOUS DISEASES in cattle

Graphic handbook of immunology and infectious diseases in cattle

Graphic handbook in cattle

IMMUNOLOGY and INFECTIOUS DISEASES in cattle

of immunology and infectious diseases

GRAPHIC HANDBOOK

AUTHORS: Ana Doménech Gómez, María del Mar Blanco

Gutiérrez, María Dolores Cid Vázquez, María Teresa Cutuli de Simón, Alberto A. Díez Guerrier, Gustavo Domínguez Bernal, Alicia Gibello Prieto, Esperanza Gómez-Lucía Duato.

FORMAT: 25 × 25 cm. NUMBER OF PAGES: 80. BINDING: hardcover.

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€75 The Graphic handbook of immunology and infectious diseases in

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cattle is an innovative book that presents the essential aspects of bovine immunology and provides key information about the main vaccine-preventable diseases in cattle and vaccination and disease control procedures. The detailed illustrations and diagrams will help veterinary surgeons consolidate their knowledge in this field. Although immunology is a complex field, thanks to their extensive teaching experience, the authors have succeeded in making this book very instructive and accessible.

Presentation of the book Infectious diseases still remain the main cause of economic losses in cattle production and a barrier to international trade. Their onset depends on the pathogenic action of infectious agents and the inadequate or insufficient immune response of the host. It is thus essential to know the basics of the immune response both for the diagnosis and the control by vaccination. This book presented here intends to be a handbook which will assist the professionals who center their activity in cattle production, especially on aspects related to basic immunology and immune response, the main diseases subject to vaccination, and the control and preventive measures. With this goal, the book is divided into three different parts. The first part addresses the main topics about the immune system â&#x20AC;&#x201C;which are the lymphoid organs and tissues, cells taking part, types of immune response and involved mechanisms, specific response against infectious and parasitic agents, and general points about immunopathology. Some relevant issues for cattle are included, like immunology of the mammary gland, immunology of pregnancy and the foetus, as well as immunology of the newborn calf, related to colostrum and the failure of antibody passive transfer. Some basic concepts about immunologic serologic diagnosis, the tuberculin test and IFN-gamma, and the detection of pathogens through PCR and ELISA, are also included. In the second part, the main features of the most relevant infectious diseases of cattle â&#x20AC;&#x201C;which are subject to vaccinationâ&#x20AC;&#x201C;, are described in a schematic way. Basic issues like aetiology, epidemiology, pathogenesis, clinical signs and lesions, as well as the diagnostic methods, applied treatment and prevention measures, are addressed. The most relevant diseases in farms are included together with the mandatory reporting diseases. Finally, the third part of the book discusses the prevention and control of bovine diseases. Control programmes in dairy, beef and extensive cattle are addressed, especially focused

Graphic handbook of immunology and infectious diseases in cattle

on calf colostrum feeding. After describing the existing vaccine types, the authors focus on the vaccination recommendations in dairy, beef and breeding cattle. The whole information is presented as full colour sheets, with schemes and computer graphs, accompanied by brief texts with the goal of making this book a didactic and enjoyable reading, but including a rigorous and updated content. On the other hand, the presentation of the topics in double page sheets makes its consultation easier and quicker, since each one is independent from the others, although given the relationship amongst concepts about immunology, there are crossed references to ease their understanding. We hope this book fulfills the proposed goal: reach the reader and ease the comprehension of essential aspects of the immune response and the infectious diseases of cattle, together with the recommendations for vaccination and control at the farm level.

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Graphic handbook of immunology and infectious diseases in cattle

The authors The authors of this book form part of the academic staff at the Department of Animal Health of the Faculty of Veterinary Medicine of the Complutense University of Madrid (UCM), where they also carry out their research activities.

Ana Doménech Gómez Book coordinator. Graduate degree and PhD in veterinary medicine from the UCM. Her teaching areas include infectious diseases, preventive medicine, health policy, zoonoses, and public health, at the graduate and postgraduate levels. Member of the Clinical Microbiology and Parasitology Service of the Veterinary Teaching Hospital of the UCM. Board member of the Spanish Virology Society, and member of the European Society for Virology, the European Association of Veterinary Laboratory Diagnosticians (EAVLD) and the Spanish Association of Veterinary Specialists in Laboratory Diagnosis (AVEDILA). She has contributed to several books on immunology and infectious diseases in veterinary medicine, as well as multiple educational innovation projects at the UCM. Her research primarily focuses on animal retroviruses, especially those of ruminants and felines. She has authored several scientific publications in specialised international journals as well as books, booklets, and review articles on retroviruses.

María del Mar Blanco Gutiérrez Graduate degree and PhD in veterinary medicine from the UCM. Her veterinary teaching and research activity focuses on microbiology, immunology, and infectious diseases. She teaches at the graduate and postgraduate levels, as well as specialised training seminars, and has been a visiting professor in Italy, Portugal, France, and Belgium as part of the Erasmus programme. She has contributed to the writing and translation of several books on immunology and infectious diseases in veterinary medicine, as well as the design and production of educational material as part of innovative teaching programmes. She is the author of numerous scientific publications in specialised international journals, as well as review articles and articles in specialist magazines. Her research has included several extended stays at institutions in both Europe and the United States, focusing on the study of host-pathogen interactions.

María Dolores Cid Vázquez Graduate degree and PhD in veterinary medicine from the UCM. She teaches Epidemiology, Infectious Diseases, Preventive Medicine, Health Policy, Zoonoses, and Public Health to graduate and postgraduate veterinary students. She has directed several innovative teaching projects in the fields of epidemiology and infectious diseases, producing diverse teaching material, including print and e-books, interactive games, and art-science exhibitions. She has directed several competitive research projects, and has collaborated with private sector companies and in international cooperative projects. She is the author of numerous articles in scientific journals, as well as booklets, book chapters, and articles in specialised magazines. Her main line of research focuses on infectious diseases of neonatal ruminants, particularly diarrhoeal and respiratory processes.

María Teresa Cutuli de Simón Graduate degree and PhD in veterinary medicine from the UCM. Head of the Mycology Sub-Service at the Clinical Microbiology and Parasitology Service of the Veterinary Teaching Hospital, UCM. She is an active collaborator in the development of new educational material within the framework of the UCM’s innovative teaching projects, including “Virtual Laboratory of Veterinary Microbiology”, “Immunotrivial pursuit: basic level” and “Immunotrivial pursuit: advanced level”, and “Viropolis”. She has coauthored several books, including the Manual de Microbiología Veterinaria (Manual of Veterinary Microbiology), Manual de Inmunología Veterinaria (Manual of Veterinary Immunology), and Guía práctica para Identificación y Diagnóstico en Micología Clínica (Practical Guide for Identification and Diagnosis in Clinical Mycology). She is also coauthor of numerous scientific publications within her area of specialisation. Her work focuses on the laboratory diagnosis of mycoses, particularly those affecting cats and dogs. Her research interests include tick biocontrol and host-pathogen interactions in trout lactococosis infections.

Alberto A. Díez Guerrier Veterinary surgeon and Associate Professor specialising in ruminants at the Department of Animal Health of the UCM. He teaches the subjects of Infectious Diseases, Parasitic Diseases, Preventive Medicine, Health Policy, Zoonoses and Public Health, and oversees rotations as part of the graduate degree in veterinary medicine. He is the head of the veterinary services of the Spanish Cattle Health Protection Agencies (ADS), and a founding partner and spokesperson of the Madrid Veterinary Association of Ruminant Specialists. In addition, he is a board member of the Official College of Veterinary surgeons of Madrid, and works both as a veterinary collaborator with the Autonomous Community of Madrid and a technical advisor on diagnostic tests for bovine tuberculosis. He has participated in Spanish and European research projects, collaborations with private enterprise, teaching projects, and international development projects. He has published several articles in international research journals, as well as booklets, review articles, and book chapters.

Graphic handbook of immunology and infectious diseases in cattle

Gustavo Domínguez Bernal Graduate degree and PhD in veterinary medicine from the UCM. He currently teaches Immunology and Infectious Diseases at the graduate and postgraduate levels. He is highly active in the public dissemination of science. He has collaborated in initiatives such as Science Week, and has worked on the development of new didactic software tools within the framework of the educational innovation projects of the UCM. He is the author of numerous scientific publications in international journals and of several reviews on the interaction between pathogens and host cells. He has been a visiting researcher in different European countries. Currently, his research focuses on the design of new vaccine strategies in the fight against viruses (porcine reproductive and respiratory syndrome virus), bacteria (Salmonella), and protozoa (Leishmania) that affect different animal species.

Alicia Gibello Prieto Graduate degree in biological sciences from the UCM. She completed her PhD at the Faculty of Veterinary Medicine, UCM. She teaches Microbiology and Immunology at the graduate and postgraduate levels, as well as specialised training seminars. She has contributed to the writing and translation of several books on veterinary immunology, as has worked on the design and production of educational material as part of the UCM’s innovative teaching projects in microbiology and immunology. Her research activity focuses on the use of microorganisms in bioremediation processes, and on host-pathogen relationships in diseases that affect aquaculture. She is particularly interested in the study of new diagnostic systems, virulence and/or pathogenicity mechanisms, and the immune response of the host. She is the author of numerous scientific publications in international and Spanish journals, as well as in specialised magazines. She completed her scientific training through research visits at different institutions in the United Kingdom, including the University of Leicester and the Institute of Food Research in Reading.

Esperanza Gómez-Lucía Duato Full Professor of Animal Health, she teaches Microbiology and Immunology at the Faculty of Veterinary Medicine. She is a current or previous board member of several scientific societies of Virology and Microbiology, and a member of the European Society for Virology. Her research has included several extended stays at universities in the USA, including Madison University (Wisconsin), Harvard University (Massachusetts), Oregon Health Sciences University (Oregon), and University of California (Davis), as well as short teaching stays in Puławy (Poland) and Munich (Germany) as part of the Erasmus programme for teachers. She is codesigner of several educational games and computer programs, including “Virtual Laboratory of Veterinary Microbiology”, “Viropolis”, “Immunotrivial pursuit: basic level” and “Immunotrivial pursuit: advanced level”, and “Vir(tu)al Epidemic”. She is also a coordinator of the Manual de Inmunología Veterinaria (Manual of Veterinary Immunology) and, as part of an Erasmus project, of the book Virology. An interactive guide, as well as several online courses. Her research focuses on animal retroviruses, in particular those of cattle, small ruminants, and felids.

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GRAPHIC HANDBOOK

IMMUNOLOGY and INFECTIOUS DISEASES in cattle

Table of contents General immunology 1. Tissues and organs of the immune system 2. Cells and molecules of the immune system 3. Innate immunity. Phagocytosis 4. Acquired immunity 5. Local and general inflammation 6. Immunoglobulins 7. Mucosal immunity 8. Immunity of the mammary gland 9. Immunity during gestation and in the foetus 10. Immunity in the neonate and calf. Colostrum. Passive antibody transfer 11. Immunity against viruses 12. Immunity against bacteria 13. Immunity against protozoa 14. Immunodeficiency and immunosuppression 15. Serological diagnosis 16. Immunological diagnosis: cellular immunity 17. Direct diagnosis: detection of antigens and nucleic acids

Vaccine-preventable bovine diseases 18. Neonatal diarrhoea in calves 19. Bovine respiratory disease 20. Diseases caused by clostridia 21. Bovine mastitis 22. Abortions in cattle 23. Bovine viral diarrhoea 24. Infectious bovine rhinotracheitis 25. Bovine tuberculosis 26. Bovine paratuberculosis 27. Bovine brucellosis 28. Bluetongue 29. Foot-and-mouth disease

Prevention and control of bovine diseases 30. Health management programmes in cattle. Colostrum feeding 31. Production and administration of vaccines 32. Vaccination recommendations in dairy, beef, and breeding cattle

TISSUES AND ORGANS OF THE IMMUNE SYSTEM The immune system consists of a collection of tissues and organs in which the cells responsible for the immune response are generated and mature, and from where most of the innate and specific immune responses are initiated.

LYMPHOID ORGANS AND TISSUES

Primary lymphoid tissues: these are the organs in which the immune cells are generated and mature. All blood and immune cells originate in the bone marrow of the long bones during foetal development. As in other species, pre-T lymphocytes mature in the thymus, which involutes with age. In bovids, pre-Blymphocytes mature in the intestinal lymphoid tissue (ileocaecal Peyer’s patches). Lymphopoiesis of B lymphocytes decreases after calving with the involution of Peyer’s patches in the adult animal. Secondary lymphoid tissues: these are the tissues and organs in which antigens are presented to and specifically recognised by lymphocytes (adaptive immunity), resulting in subsequent lymphocyte activation. These include the lymph nodes, the haemal nodes, the spleen, and the mucosa-associated lymphoid tissue (MALT).

Peyer’s patches

Spleen Thymus Bone marrow

Immune responses to antigens carried in the lymph are initiated in the lymph nodes, which are distributed throughout the body. Palpation of the superficial lymph nodes is important in the diagnosis of certain infectious processes. An increase in lymph node size is indicative of infection.

UDDER OR MAMMARY GLAND

Responses to Ag carried in the blood are initiated in the spleen. In addition to its immune functions, the spleen removes aged cells from the blood and iron from haemoglobin, and stores red blood cells.

Responses against ingested or inhaled antigens are usually initiated in the MALT, and induce a local and systemic response. In bovids, the mammary gland is of great immune importance, and fulfils two functions: producing colostrum, by which immunity is transferred to the calf; and maintaining its own protection through innate and acquired immune factors. Given that the cell number increases in response to infection, the somatic cell count (SCC) in milk (number of leukocytes per millilitre of milk) is a useful indicator of inflammation of the mammary gland.

Colostrum

Somatic cells

Chart

LYMPHATIC SYSTEM OF THE COW Parotid lymph node

Subiliac lymph node

Retropharyngeal nodule

The haemal nodes form a complex network of nodules associated with the blood and lymphatic systems, and receive all cells and antigens via the blood. These nodes contain numerous erythrocytes and mediate multiple functions, including erythropoiesis, phagocytosis, and initiation of the specific immune response.

Continuous movement of immune cells between blood, lymph, and tissues ensures adequate control and elimination of foreign agents.

Bone marrow Thymus Spleen Peyerâ&#x20AC;&#x2122;s patches Mandibular lymph node Superficial cervical (prescapular) lymph node

Inguinal lymph node

LYMPH NODES AND LYMPHATIC CAPILLARIES

Venule

Afferent lymphatic vessel Primary lymphoid follicle Arteriole

Efferent lymphatic vessel

Lymphatic capillary

IMMUNITY IN THE NEONATE AND CALF. COLOSTRUM. PASSIVE ANTIBODY TRANSFER The bovine placenta does not allow the transfer of antibodies from the blood of the mother to the foetus during gestation. The newborn calf is confronted with an environment rich in microorganisms and its capacity to mount an immune response is limited. It is thus essential to acquire maternal antibodies through colostrum.

At the moment of birth, the calf’s immune system is only partially functional. Furthermore, immunity may be compromised by stress (e.g. cold, the absence of visual contact with other calves, absence of the mother).

Colostrum contains the accumulated secretions of the mammary gland during the final stages of gestation. Most Igs (Abs) are transferred from the blood of the cow to her udder during the 6 weeks prior to calving, an in particular during the last 2 to 3 weeks. Premature calving or an excessively short dry period can reduce Ig levels in colostrum.

Prepartum vaccination (between 12 and 3 weeks before the expected calving date) generates an increase in specific Igs against pathogens in the blood of the pregnant female. These Igs are transferred to the udder during the final weeks of gestation. Colostrum rich in these Igs will protect the neonate against infections caused by these agents.

Antibodies Mammary alveolus

IgG IgM

The most abundant forms of Ig in colostrum are IgG, IgM, and IgA. Colostrum also contains cells, mainly lymphocytes, neutrophils, and macrophages. These leukocytes provide passive immunity to the newborn at the local level (in the intestine), and also stimulate development of the immune system. COMPOSITION OF COW COLOSTRUM Concentration (mg/dl)

Immunoglobulin

IgA

Colostrum

Milk

IgG (IgG1 and IgG2)

2,400–8,000

50–750

IgM

300–1,300

10–20

IgA

100–700

10–50

Adapted from Tizard, IR (2009). Introduction to Veterinary Immunology (8th Ed.). Ed. Elsevier. Madrid.

Chart

ABSORPTION OF IMMUNOGLOBULINS (Ig) IN THE CALF INTESTINE

Rumen Omasum

The amount of Ig absorbed depends on moment at which colostrum is ingested, the volume ingested, the concentration of Ig in colostrum, and the efficiency of intestinal Ig absorption. Ig absorption is greatest at 6 to 8 hours postpartum, and virtually disappears by 24 hours postpartum.

Intestine

ABSORPTION OF COLOSTRAL Ig Oesophageal groove

Abomasum

A DELAY IN THE CALF’S FIRST INTAKE OF COLOSTRUM IS ONE OF THE MOST FREQUENT CAUSES OF INSUFFICIENT Ab LEVELS.

100

Enterocytes Absorption

80 60 40 20 0

12 h 18 h Hours postpartum

24 h

Ab concentration

CONCENTRATION OF Ab IN CALF

Passive immunity (colostrum) Active immunity

14 21 Age in days

Immune transfer via colostrum can be evaluated by determining total serum solids (TSS) in calf serum. This is the most reliable parameter to estimate the calf’s overall resistance to infection.

As maternal Abs fade, the calf produces its own Abs. If Ig intake from colostrum is low, the risk of infection will remain high until the calf’s immune system reaches maturity.

Incorrect timing of vaccination in calves can be counterproductive, as passively transferred Abs will neutralise vaccine antigens, preventing the development of an active response by the calf’s immune system. 31

NEONATAL DIARRHOEA IN CALVES AETIOLOGY

The following are the main enteropathogens of calves, and are implicated in both simple and mixed infections:

1. Bovine rotavirus: family Reoviridae (nonenveloped RNA virus).

2. Bovine coronavirus: family Coronaviridae

DISTRIBUTION OF ENTEROPATHOGENS WITH AGE

(enveloped RNA virus).

3. Escherichia coli: gram-negative rod, normal inhabitant of the intestine. Strains that produce diarrhoea in calves include: ■

■

Enterotoxigenic E. coli (ETEC). Colonises the intestine by means of F5 (K99) or F41 fimbriae and produces STa enterotoxin. Enteropathogenic E. coli (EPEC). Produces attachment and effacement lesions of the intestine.

4. Cryptosporidium parvum: protozoan of the phylum Apicomplexa.

EPIDEMIOLOGY PRESENTATION

ETEC ETEC Diarrhoea Diarrhoea

Rotavirus, coronavirus,EPEC, EPEC, Rotavirus, coronavirus, Cryptosporidium Cryptosporidium parvum Infection andand shedding enteropathogens in the faeces Infection faecalofshedding of enteropathogens

Infection Infection Daysof oflife life Days 00

Constitutes the main cause of mortality in calves in the first weeks of life. Causes significant economic losses due to mortality and stunting.

Affects neonates (0–4 weeks). Worldwide distribution. Causal agents are widely distributed on farms. Some are potentially zoonotic.

TRANSMISSION

Faecal-oral route. Neonates are infected via faecal contamination in the environment. Healthy animals can act as carriers and shed enteropathogens that survive in the environment for weeks. Diarrhoeic animals shed large amounts of enteropathogens, thus amplifying environmental contamination.

RISK FACTORS

In general, the associated risk factors are those related to calf immunity (colostrum intake, nutrition, and vaccination of mothers) and those that increase the level of faecal contamination in the environment (high density of animals, poor hygiene, etc.).

The main risk factor is an inadequate level of colostral immunity in neonates.

Chart

PATHOGENESIS

CLINICAL SIGNS

Short incubation period. Rotavirus and coronavirus, EPEC, and C. parvum cause diarrhoea due to malabsorption. ETEC produces secretory diarrhoea.

■ Anorexia, depression, decreased sucking

PATHOGENESIS OF MALABSORPTION DIARRHOEA

Acute course. reflex, and weight loss until cachexia. protrusion of bones, and enophthalmos. Dryness of mucous membranes, cold ears and extremities, and tachycardia. acidosis or hypovolaemic shock.

LESIONS Dehydration, emaciation, dilated intestinal loops containing yellowish fluid.

Supportive treatment should be immediately administered, without waiting for the laboratory diagnosis. Oral or intravenous fluid therapy, depending on the degree of dehydration, to correct metabolic acidosis and dehydration. Antibiotic treatment should be administered empirically: ineffective against diarrhoea-causing viruses and protozoa, and no clinical trials of the efficacy of EPEC treatment have been conducted.

CONTROL ■ Increase resistance of neonates: vaccinate

mothers before calving and ensure adequate colostrum intake. Multivalent vaccines against rotavirus, coronavirus, and ETEC are available.

1 Damage of enterocytes and substitution with immature cells. 2 Atrophy of intestinal villi. 3 Alterations of digestive enzymes (lactase) and decreased use of lactose. 4 Malabsorption. 5 Diarrhoea and dehydration. 6 Loss of electrolytes and metabolic acidosis.

STa

TREATMENT

■ Dehydration: Loss of skin elasticity,

■ Death from dehydration and metabolic

PATHOGENESIS OF SECRETORY DIARRHOEA

■ Reduce environmental contamination:

cleaning and disinfection, individual housing, and separation of sick animals.

Perineal region stained with faeces.

Vaccination without controlling for risk factors is not sufficient to prevent diarrhoea.

DIAGNOSIS Laboratory diagnosis should include samples from diarrhoeic and healthy animals. ■ Joint detection of rotavirus, coronavirus, ETEC and C. parvum

antigens: Rapid ELISA and immunochromatography. ■ Detection of nucleic acids: PCR. 1 Bacteria bind to microvilli of enterocytes via fimbriae. 2 They multiply and produce STa toxin. 3 STa alters the secretion/absorption process. 4 Diarrhoea and dehydration. 5 Loss of electrolytes and metabolic acidosis.

The isolation and identification of E. coli in faecal samples, without determining virulence factors by PCR, is not significant as this species is a normal inhabitant of the intestine. Commercial rapid immunochromatography test.

PRODUCTION AND ADMINISTRATION OF VACCINES The objective of vaccination is to develop a specific immune memory against a particular pathogen. In this way, when the vaccinated animal is naturally infected, the response to the pathogen will be faster and more efficient.

ATTENUATED (LIVE) VACCINES

INACTIVATED (DEAD) VACCINES

A vaccine consists of the modified pathogen (viruses, bacteria, protozoa), any of its antigenic components, or the toxins they produce. Vaccine Ag is safe for the animal, but is capable of stimulating a protective immune response.

Attenuated and inactivated vaccines are the most commonly used forms in cattle. In general, attenuated vaccines confer a more intense and lasting immunity, since they induce an immune response similar to that induced by a natural infection. However, they are less safe than inactivated vaccines.

Vaccines containing inactivated microorganisms, or their toxins (referred to as toxoids, as found in vaccines against clostridial toxins), are less potent, and therefore usually also contain adjuvants, i.e. substances which, when inoculated together with an Ag, enhance the immune response. The most commonly used are aluminium hydroxide, mineral oils, and saponins.

Most bovine vaccines are multivalent: they contain different microorganisms implicated in processes within a given organ system. For example, the inactivated vaccine administered to pregnant females to prevent neonatal diarrhoea in calves contains rotavirus, coronavirus, and ETEC strains (see Chart 18).

Monovalent vaccines contain a single microorganism. Sometimes they can be even more specific, containing the most appropriate strain or serotype for a given area (e.g. bluetongue vaccine) (see ChartÂ 28).

Autogenous vaccines contain one or more microbial strains isolated from a farm, and are used to vaccinate animals from that specific farm. They can be used to prevent mastitis (see Chart 21).

Safety

Efficacy

Safety

Efficacy

MULTIVALENT VACCINES

Colostrum

4 Neonatal diarrhoea

MONOVALENT VACCINES

5 Bluetongue

AUTOGENOUS VACCINES

6 Mastitis

Chart

ADMINISTRATION OF VACCINES 7

It is essential that animals to be vaccinated are healthy. Most vaccines are administered via the subcutaneous or intramuscular route. Some attenuated vaccines against respiratory processes can also be administered intranasally.

Vaccines do not confer immediate protection after administration, as activation of the specific immune system and the development of immunological memory are necessary. The duration of immunity depends on various factors, and it is common for animals to be revaccinated (see Chart 32).

Neonates acquire immunity via colostrum. The presence of colostral Abs can prevent the development of an active immune response by the calf (see Chart 10). It is therefore important to adhere to the recommended vaccination schedule (see Chart 32).

Occasionally, the immune response to the vaccine may interfere with diagnostic testing. Marked or DIVA (Differentiating Infected from Vaccinated Animals) vaccines allow differentiation between infected and vaccinated animals. Examples include vaccines against infectious bovine rhinotracheitis (IBR) (see Chart 24).

Vaccination may induce temporary local inflammation at the point of inoculation, or a slight increase in body temperature. Severe adverse reactions (hypersensitivity) are rare, and should be reported immediately.

Intranasal route Intramuscular (IM) route Subcutaneous (SC) route

IM: neck (preferred), buttock (not recommended) SC: neck (preferred), postscapular zone (always behind the scapula), and caudal fold (both sides of the root of the tail)

TYPES OF VACCINES CLASSICAL VACCINES Attenuated Live attenuated microorganisms.

SECOND GENERATION VACCINES Inactivated

Inactivated toxins / Inactivated microorganisms (dead).

Antigens (molecules) of the pathogen produced in a laboratory.

Genetically modified microorganisms.

IMMUNOMODULATORS Immunomodulators or immunostimulants are substances that improve the immune response. They can be administered to the animal along with Ag (i.e. as part of the vaccine), or to reduce clinical signs in the case of an infection (e.g. mastitis).

Administration of a subcutaneous vaccine using a dosing gun.

The publishing strength of Grupo AsĂs Editorial Servet, a division of Grupo AsĂs, has become one of the reference publishing companies in the veterinary sector worldwide. More than 15 years of experience in the publishing of contents about veterinary medicine guarantees the quality of its work. With a wide national and international distribution, the books in its catalogue are present in many different countries and have been translated into nine languages to date: English, French, Portuguese, German, Italian, Turkish, Japanese, Russian and Chinese. Its identifying characteristic is a large multidisciplinary team formed by doctors and graduates in Veterinary Medicine and Fine Arts, and specialised designers with a great knowledge of the sector in which they work. Every book is subject to thorough technical and linguistic reviews and analyses, which allow the creation of works with a unique design and excellent contents. Servet works with the most renowned national and international authors to include the topics most demanded by veterinary surgeons in its catalogue. In addition to its own works, Servet also prepares books for companies and the main multinational companies in the sector are among its clients.

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