Integrity
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Zoonotic Diseases
(Clostridial myositis: black leg, malignant edema, gas gangrene. Enterotoxemia: pulpy kidney, struck, lamb dysentery, braxy. Tetanus: lockjaw) AGENT:Clostridium tetani (horses)--tetanus. Clostridium perfringens (cattle, sheep)--gas gangrene. Clostridium septicum (cattle)--malignant edema. RESERVOIR AND INCIDENCEClostridia are normal intestinal flora and also survive by spores in the soil. TRANSMISSION:Infection may be by contamination of deep, penetrating wounds to cause tetanus, by ingestion of preformed toxin or spores which vegetate in the digestive tract to cause enterotoxemia, or by ingestion of spores which are carried by the blood to muscles where they remain dormant until activated by trauma to produce necrotizing myositis. C. perfringens food poisoning is due to spore contamination of foods which survive heating to vegetate in unrefrigerated conditions. Neonatal tetanus in humans is frequently caused by contamination of the umbilicus. DISEASE IN ANIMALS:Tetanus: as in humans. In myositis (black leg) cases a limb is still and painful with crepitus on palpation. Signs of toxemia. Rapidly fatal. C. chauvoei, novyi, and septicum toxins produce massive muscle necrosis, often with edema and SC gas formation. C. perfringens causes a variety of profound toxemias with cloudy swelling of parenchymatous organs and excess fluids, often bloodstained in serous cavities. DISEASE IN MAN:Tetanus: painful toxic contractions of muscles and trismus (a tonic contraction of the muscles of mastication). The case fatality rate for tetanus is 30-90% even when treated. Gas gangrene: fever, toxemia, painful edema spreading from the edges of wounds, interstitial emphysema, neck stiffness. Food poisoning: vomiting and diarrhea of a few days' duration. TREATMENT:Myositis: penicillin, adequate surgical debridement and exposure of infected areas. Tetanus: immune globulin, penicillin, mechanical ventilation. Spasms are controlled with chlorpromazine or diazepam combined with a sedative. PREVENTION/CONTROL:Immunization with toxoids (good for 10 years), proper treatment of wounds. Good food hygiene is essential. In animals, prevent wound contamination during lambing, shearing, castration and docking. |