Rattlesnake envenomation in 12 New World camelids

BACKGROUND: Rattlesnake envenomation of New World camelids is a seasonal problem with often dramatic clinical signs. HYPOTHESIS: The purpose of this study was to identify the clinical signs, laboratory results, treatment methods, and outcome for rattlesnake envenomation in New World camelids. ANIMALS: Medical records from 1988 to 2004 were searched for New World camelids presented for rattlesnake bite or clinical signs suspected to be related to recent envenomation. Twelve records were identified. METHODS: From these records a retrospective study was performed. RESULTS: Nine camelids presented for acute disease (2/9 arrived dead), whereas 3 presented for subacute onset of disease. Swelling of the lips, head and neck, tachypnea, dyspnea, tachycardia, and lethargy were the most common presenting signs. Snake bites were most commonly located to the muzzle (10/12). Common complete blood count (CBC) and serum biochemical abnormalities were neutrophilia, lymphopenia, increased muscle enzyme activity, hypoalbuminemia, hyperglycemia, hypokalemia, and thrombocytopenia. Treatment included combinations of intravenous fluid therapy, antimicrobials, anti-inflammatory drugs, tetanus prophylaxis, tracheostomy, supplemental oxygen, antivenom, total parenteral nutrition, and nursing care. Five of the 10 animals with acute onset of clinical signs survived, and all animals with subacute presentation died. The mortality rate for New World camelids with severe local tissue reaction and systemic signs of envenomation was 58%. CLINICAL IMPORTANCE: New World camelids that sustain rattlesnake envenomation and severe facial swelling precluding prehension and mastication have a guarded prognosis for survival. Aggressive treatment is recommended to optimize the chances of survival. Animals with less severe local tissue reaction and absence of systemic signs have a better prognosis.