South American rattlesnake (Crotalus durissus spp) envenomation in dogs in the semiarid region of Brazil

ABSTRACT

Background: South American rattlesnake (Crotalus durissus spp.) envenomation is rarely reported in small animals andlivestock in Brazil. Minor swelling at the snakebite site, skeletal muscle, and renal damage, and severe neurological signscharacterize the crotalic envenomation. This case report aims to present epidemiological, clinical, and pathological dataof two cases of Crotalus durissus spp envenomation in dogs in the Northeast of Brazil.Cases Envenomation by Crotalus durissus spp. was recorded in two dogs in Patos, State of Paraíba, Brazil. In Case 1,the dog presented flaccid paralysis, hyporeflexia, a deficit of cranial nerves, epistaxis, and gingival hemorrhages. Laboratory assay showed proteinuria, myoglobinuria, regenerative thrombocytopenia, and increased serum activities of creatinekinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The dogwas medicated with crotalic antivenom and wholly recovered from local and systemic clinical signs. In Case 2, the dogdied and was detected fang marks at the ventral region of the left mandible (two small parallel perforations spaced 2.0 cmapart) at the snakebite site. Cyanosis of the oral cavity, congestion, and hemorrhages in several organs were observed atnecropsy. Tubular nephrosis, muscular necrosis, hepatocytes swelling were observed. The owners witnessed snakebites,and the rattlesnakes (Crotalus durissus spp.) identified by the rattle at the end portion of the tail in both cases.Discussion: Natural South American rattlesnake envenomation presents complex clinical signs that makes diagnosis achallenge for veterinary practitioners. The criteria for the correct diagnosis and observed in the two dogs include witness ofthe snakebite, identification of the snake, detection of fang marks, clinical-pathological findings, and therapeutic responseto treatment with specific anti-venom....