CLOSTRIDIAL DISEASES IN CATTLE

CLOSTRIDIAL DISEASES

In Cattle

By Lee Jones, DVM, MS, University of Georgia

Clostridium spp are anaerobic, spore-forming bacteria found in the environment and intestinal tracts of many animals.

They exist in the environment in two forms: living bacteria or dormant spores. Some dormant spores can even be found in tissues of healthy animals. Some of the organisms invade tissue and produce toxins while others produce toxins outside the body that are absorbed or ingested by the unsuspecting animal. Diseases caused by Clostridia spp are nearly always fatal. Many times, animals affected by Clostridia spp are suddenly found dead with no clinical signs observed. Blackleg

Probably, the most common disease caused by these organisms known to most farmers is blackleg caused by Clostridium chauvoei. Mostly, blackleg affects animals under 2 years old but can affect older, non-vaccinated animals too. The spores are ingested or already circulating in the animal and infect muscle tissue usually following injury such as bruising or other trauma. The infection causes swelling in the muscles and subcutaneous tissues, which leads to lameness. Gas bubbles can often be felt under the skin like small bubble-wrap packaging material. The animal is usually extremely lame and has a high fever, though most times the disease progresses so rapidly that the animal is often found dead. At postmortem examination (autopsy), the muscle is almost black (hence the name) and necrotic with gas pockets under the skin and in the tissue. A rancid odor might be noticed. Diagnosis is usually from characteristic necropsy lesions, but a laboratory can confirm presence of C. chauvoei bacteria. Red Water Disease

Clinically called bacillary hemoglobinuria, the disease is caused by C. haemolyticum. Red water gets its name from hemoglobin making the urine red. The spores of the organism germinate in the liver following trauma or injury caused by liver fluke, abscess or infection, liver biopsy or other cause of liver damage. Toxins from the organism destroy red blood cells releasing hemoglobin, which collects in the bladder. Symptoms include severe depression, fever, difficulty breathing, anemia and gut pain (colic). Postmortem signs might include an offcolored area of liver necrosis, blood in intestine and red urine. Animals are usually suddenly found dead and treatment of affected animals is often unsuccessful. Enterotoxemia

Enterotoxemia, also known as overeating disease, is a common disease affecting young, rapidly growing livestock including cattle, sheep, goats and even foals. It is caused by enterotoxins produced in the intestines from C. perfringens types A, B, C or D. Different types usually affect different species, with D mostly affecting sheep and goats but occasionally cattle; type C affects cattle but infrequently also types B and A sometimes affect adult cattle. In young livestock, it is often an acute disease, with many dying before clinical symptoms are seen. Usually, sudden death of the best-growing, unvaccinated animals is the first sign. In calves, there might be diarrhea, but abdominal pain (colic signs) and convulsions often precede death. Sometimes animals found dead may have signs of paddling where the legs were moving on the ground as the animal suffered a painful death. On necropsy,

bloody inflammation of the small intestine is common. The small intestine is usually bright red or deep purple, depending on how long the animal has been dead before examination. The pericardial sac is often fluid filled with areas or spots of reddening in the heart muscle. Malignant Edema

Malignant edema is a disease caused by C. septicum. Like other Clostirial bacteria, it also is commonly found in the environment and feces of livestock. It gains entrance into the body through wounds and can be introduced into the birth canal following a difficulty in calving causing an infection in the tissues around bruised or injured tissue. Symptoms include not eating, high fever, depression or lethargy, and severe swelling around the infected site. Animals often become “toxic” and die within 48 hours of infection. The swollen tissue may “pit” when pressed due to excessive fluid accumulation. Gas formation is uncommon. On necropsy, the tissue will be wet, dark, necrotic and foul-smelling. Black Disease (Infectious Necrotic Hepatitis)

Spores of C. novyi circulate through the body and lodge in the liver. The organism multiplies in damaged tissue following liver fluke migration and produces a potent necrotizing toxin (alpha toxin). The toxin may cause portions of the skin to die and turn black, hence the name. Necropsy usually includes grayish to yellow necrotic liver tissue as well as migratory tracts or scars from flukes. Often, there may also be an enlarged heart sac and fluid in the chest. C. sordellii

Infections can lead to GI or muscle infections. Generally, the first sign is sudden death. More commonly found in feedlots, the most frequent findings on necropsy are severe swelling and necrosis in the neck and brisket often accompanied by a foul odor. Tetanus

Tetanus is caused by toxins produced by a neurotoxin produced by C. tetani in necrotic tissue. Many animals are susceptible, including humans; however, dogs and cats seem more resistant, with horses, lambs and people being most susceptible. While relatively rare in drier, cooler climates, C. tetani is common in warmer, wetter regions, especially in cultivated soil and areas contaminated with fecal material. The spores are not able to grow in normal viable tissue. However, favorable conditions of necrotic tissues allow the bacteria to multiply. As the cells die, they release neurotoxin. The toxin causes localized uncontrolled spasms of voluntary muscles, often affecting the muscles of the mouth (hence the common name “lockjaw”) but quickly spreads to other parts of the body as the toxin circulates in the blood. Affected animals may go into full body rigid spasms and even respiratory failure. Though cattle are more resistant than sheep and goats, it can occur 2-4 weeks following banding of scrotum, tail or horns. Animals need to be given a vaccine containing tetanus toxoid at the time of banding. Some producers also give tetanus antitoxin, though the practice may not be beneficial due to the long incubation time and clearance of the antitoxin within 7-10 days. Vaccination with tetanus toxoid appears to be more effective. The common 7-way vaccines do not contain tetanus. Read labels carefully to see if the vaccine contains tetanus. If animals do get tetanus, treatment with antitoxin and removing the necrotic tissue may help, but retreatment is required and recovery can be very long. Most of the time, animals do not respond. Botulism

Botulism is caused by animals consuming toxins in food produced by C. botulinum. There are seven types (A through G) – with A, B and E affecting people and D most often affecting cattle. The common source of botulism poisoning is decaying carcasses in animal feed such as silage or haylage but also potentially spoiled silage, decaying grasses or grain. Botulism cases in cattle are quite rare in the U.S. and occasionally occur in horses, but widespread outbreaks in migratory waterfowl are common. Botulism causes a flaccid muscle paralysis that usually progresses to generalized paralysis, difficulty chewing and swallowing, and death by respiratory or cardiac paralysis. Some outbreaks in cattle occur after feeding silage contaminated by a decaying carcass. Typical signs include loss of control of tongue and progressive paralysis. Treatment is usually futile. C. difficile

C. difficile is a common environmental bacteria that causes diarrhea and colitis in many livestock species as well as humans. Care should be used when caring for calves with diarrhea, as humans can contract C. difficile from livestock if good hygiene is not practiced. Silage or haylage/baleage can be contaminated if a lot of dirt is picked up during harvesting. Maintaining silage cutting height to avoid cutting stalks too low helps keep ensiled feed free from C. difficile. Adult cattle can get a chronic diarrhea from consuming feed with C. difficile. Diseases caused by Clostridium spp typically affect one animal at a time, rarely causing disease in multiple animals at the same time. Clostridial disease is not contagious (spread from animal to animal). Animals acquire the bacteria from the environment. Most of the time, animals die from diseases caused by Clostridia so quickly that there is no chance to treat one and treatment is often “too little, too late” if attempted. Even if symptoms are observed, owners need to be able to quickly diagnose and treat appropriately. Penicillin is the antibiotic of choice for most Clostridial infections. However, antibiotics are effective only against the bacteria but not against the toxins produced. Other additional care may be needed and beneficial. Consult with your veterinarian as soon as possible if you suspect a problem related to Clostridial disease.

Vaccines stimulate very effective immune protection, and all cattle should receive at least two doses prior to weaning or before 1 year of age. Read and follow label directions and make sure the vaccine contains the protection you want. Most common Clostridial bacterin/toxoid vaccines (frequently referred to as 7-way vaccines) contain chauvoei, septicum, novyi, soredellii and perfringens C and D toxoid. Most do not contain haemolyticum or tetanus, but there are combination vaccines available that also contain one or both of these.