RATTLESNAKE VENOM POISONING IN HORSES - 32 CASES (1973-1993)

Objective-To determine the clinical manifestations, morbidity, mortali ty, and treatment methods for rattlesnake venom poisoning in horses. D esign-Retrospective analysis of medical records. Animals-27 horses wit h acute venom poisoning attributable to prairie rattlesnakes, and 5 wi th chronic problems subsequent to a rattlesnake bite. Results-Most hor ses were bitten on or near the muzzle while on pasture, resulting in h ead swelling, dyspnea, and epistaxis. Additional manifestations of acu te poisoning included fever, tachycardia, tachypnea, cardiac arrhythmi a, hemolytic anemia, thrombocytopenia, hemorrhage, thrombosis of venip uncture sites, colic, diarrhea, and prehensile and masticatory dysfunc tion. Chronic problems included cardiac disease, pneumonia, laminitis, pharyngeal paralysis, and wound complications. The most common chroni c problem was cardiac disease. The most commonly used treatments were antibiotics, nonsteroidal anti-inflammatory drugs, tetanus prophylaxis , and airway support. Mortality in the 27 acutely affected horses was 18.5%; the overall mortality was 25%. Clinical Implications-Horses bit ten by prairie rattlesnakes may develop multiple, often severe, acute or chronic manifestations oi poisoning involving various organ systems . Thorough clinical evaluation, effective treat ment, supportive care, and close observation are indicated in horses with rattlesnake venom poisoning.