Blackleg and Clostridial Diseases

DIVISION OF AGRICULTURE RESEARCH & EXTENSION UJA--University of Arkansas System Agriculture and atural Resources FSA3073 Livestock Health eries Blackleg and Other Clostridial Diseases symptoms. Therefore, prevention of Heidi Ward, Introduction these diseases through immunization VM, Ph Clostridial bacteria cause several is more successful than trying to treat Assistant Professor diseases that affect cattle and other infected animals. and Veterinarian farm animals. This group of bacteria is known to produce toxins with varying effects based on the way they enter the Blackleg Jeremy Powell, body. The bacteria are frequently Blackleg, or clostridial myositis, VM, Ph found in the environment (primarily in affects cattle worldwide and is caused Professor the soil) and tend to multiply in warm by Clostridium chauvoei. Susceptible weather following heavy rain. The animals first ingest endospores. The bacteria are also found in the intes - endospores then cross over the gastro - tinal tracts of healthy farm animals, intestinal tract and enter the blood- where they only cause disease under stream where they are deposited in certain circumstances. The most muscle tissue in the animal’s body. common diseases caused by clostridial They then lie dormant in the tissue bacteria in beef cattle are blackleg, until they become activated and enterotoxemia, malignant edema, black trigger the disease. disease and tetanus. These diseases Clostridium chauvoei is activated are usually seen in young cattle (less in an anaerobic (oxygen deficient) than 2 years of age) and are widely environment such as damaged, distributed throughout Arkansas. devitalized or bruised tissue. Events Bacteria of the Clostridium genus such as transport, rough handling or produce long-lived structures called aggressive pasture activity can lead to endospores. Endospores are forms of muscle damage that compromises bacteria that are extremely resistant to blood flow, resulting in decreased environmental conditions (heat, oxygen delivery to that area. In these drought, UV radiation and chemical areas of damage, the clostridial endo- disinfectants). When endospores are spores germinate and multiply into the introduced into an animal, they can disease-causing bacteria. Open wounds develop into the infectious bacteria. are not necessary for this disease to Once the bacteria begin to grow, they develop, making diagnosis difficult. cause disease by producing and Although blackleg has occurred releasing toxins into the animal’s body. in calves as young as 2 months of age, Clostridial diseases are typically the disease generally affects animals Arkansas Is infectious but not contagious. In other between 6 months and 2 years of Our Ca pus words, cattle that become infected will age as they are rapidly growing. not directly transmit the disease to Occasion ally, infections may be seen other cattle. Animals afflicted with in immuno compromised adult cattle. clostridial diseases usually die very In Arkansas, blackleg infections typi- Visit our web site at: s .uada cally occur during the late summer http ://www.uaex .edu quickly, sometimes without any prior University of Arkansas, United States epartment of Agriculture, and County Governments Cooperating and early fall, when weather is warm and wet. susceptible to tetanus than other domestic livestock Incidence of disease increases after floods due to such as horses; however, they are still at risk. Clos - endospores rising to the surface of the soil or during tridium tetani is introduced into the animal’s body drought when grass is very low, which allows cattle to through injury such as deep puncture wounds, ingest spores more readily when grazing. castration, banding and dehorning. Animals infected with blackleg usually die The incubation period for tetanus is approximately rapidly without any signs of illness. If clinical signs 10 to 21 days. Clostridium tetani produces a very are seen very early in the progression of disease, potent toxin that affects the nervous system. Clinical they will include lameness, loss of appetite, high fever signs that develop include flared nostrils, prolapsed and depression. Animals quickly die within 12 to third eyelid, stiff tail, extended “sawhorse” stance and 48 hours after contracting the disease. Although treat- difficulty chewing food (hence the name “lock jaw”). ment usually fails, appropriate doses of penicillin may Affected animals will exhibit severe muscle tremors prove helpful. If an animal does survive, it will suffer and will experience violent spasms when stimulated by from a permanent defect in the tissue where the touch or sudden sounds. infection occurred. A veterinarian can treat tetanus with antibiotics, Swelling of affected muscle tissue (leg, neck, hip, tetanus antitoxin and supportive therapy if detected chest, shoulder or elsewhere) is the most common early in the disease process. Additional medication to clinical sign of blackleg seen in dead animals. The control seizures may be needed. Intravenous fluids are swelling is due to fluid and gas accumulation produced indicated to control dehydration if the animal cannot eat by the anaerobic bacteria in the muscle tissue. When or drink. Prevention can be achieved through vaccina- pressure is applied to the affected areas, gas can often tion and diligence in using clean surgical instruments be felt moving while producing a crackling sound when castrating or dehorning. under the skin. Affected muscle tissue will contain dark areas of necrotic tissue that gives off a foul odor Malignant Edema often described as rancid butter. Malignant edema is caused by the bacteria Clostridium septicum. This clostridial bacteria is found Immunization is an inexpensive and effective way to in the intestinal tracts of most domestic livestock where prevent blackleg. Calves should be vaccinated between it is shed in feces that in turn contaminate the pasture. 2 and 3 months of age. Until that age, calves should be Malignant edema develops when the bacteria enters the protected through passive transfer of antibodies from body through an open wound. Once in the body, the their dam’s colostrum. A regular vaccination protocol bacteria invade the subcutaneous tissue, causing should be followed at weaning. Calves should receive localized fluid accumulation (edema). Symptoms may vaccine dosages according to the manufacturer’s label. include decreased appetite, high fever and localized Some vaccines require one injection followed by a swelling near the injured area. Lesions in the dead booster in 2 to 6 weeks. Other vaccines are now animal include darkened discoloration of the affected approved for a single dose injection. The common tissue and a foul odor, but the tissue swelling will not blackleg vaccines are called “7-way” because they also have gas accumulation. Death occurs quickly after infec- protect against other clostridial diseases. In accordance tion, so treatment with an antibiotic is only effective if with Beef Quality Assurance standards, vaccines should started very early in the disease. Malignant edema is always be given subcutaneously (under the skin) in the neck area. also best controlled through immunization of cattle. If an outbreak of this disease occurs, the producer Red Water should contact his her local veterinarian to initiate an Red water disease is caused by the bacteria action plan. The veterinarian may recommend that all Clostridium haemolyticum. These bacteria gain entry animals receive immediate vaccination and followup into the animal’s body by crossing the intestinal lining boosters. Further losses may occur for a 2-week period after ingestion of spores. These spores eventually lodge until the animals develop immunity against the disease. in the liver where they lie dormant until the conditions Carcass disposal should be done carefully by burying are right for them to replicate and grow. Damage to carcasses deeply where they lie as movement of the the liver by liver flukes (Fasciola hepatica) is often the carcass can further contaminate the pasture with trigger for the spores to become active, which is why clostridial endospores. this disease is limited geographically. Aquatic snails are needed for flukes to complete their life cycle, so Tetanus cattle must be in areas with considerable standing Tetanus is a disease caused by Clostridium water. If no liver damage occurs, the conditions will tetani, a bacterium found worldwide in soil and in not be right for growth of the bacteria. the intestinal tracts of many animals. Cattle are less Once infection begins, Clostridium haemolyticum weakness, abdominal distention, bloody diarrhea, releases a toxin into the blood that attacks and uneasiness (straining or kicking at abdomen) and destroys red blood cells. The resulting damage leads convulsions. Postmortem lesions normally seen are to a reddish discoloration of the urine, hence the bloody, fluid-filled small intestines that give rise to the name “red water disease.” Early treatment is essential common name “purple gut.” if the animal is to survive. Otherwise, some animals Calves with this disease need immediate treatment may be found dead before clinical signs are noticed. with intravenous fluid therapy with electrolytes to Symptoms include red urine, dehydration, fever, labored breathing, pale to yellow mucous membranes correct dehydration and acid-base imbalance. Antitoxins and anemia. Prevention of this disease is through and a broad-spectrum antibiotic are usually given in immunization and control of fluke infections through

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