Toad envenoming in dogs: effects and treatment

Abstract

Toads (order: Anura; family: Bufonidae; genus: Bufo) are distributed throughout the world, but more species are found in areas of tropical and humid temperate climates. Although toads do not have a venom inoculation system, they are venomous animals because the glands covering the whole surface of their bodies secrete a milk-like venom of which composition is not yet completely known. Some of these glands are the bilateral glands located in post-orbital position. These glands, which are somewhat diamond-shaped and can be seen by the naked eye, are known as parotids. Toad envenoming in dogs may cause local and systemic alterations and may cause death by cardiac ventricular fibrillation. The electrocardiographic alterations observed consist of gradual deterioration of the normal standards with progressive appearance of negative ventricular deflections that can result in ventricular fibrillation and death if the envenomed dog is not promptly treated. Traditional therapy consists mainly of administration of atropine and propranolol; the latter used to prevent ventricular fibrillation

Clinical and electrocardiographic evaluation during experimental toad poisoning in dogs

“…These signs are related to the action of bufotoxin on the gastrointestinal mucosa (12,17). All gastrointestinal signs were selflimited and disappeared with no specific treatment 48 hours after the administration of Bufo schineideri venom.…”

“…The neurological signs observed during this experiment agreed with those described in the literature (7-9, 14-16) and developed due to bufotenines, dihydro-butenines and bufotyonines. These substances have hallucinogenic effects on the central nervous system (17).…”

“…Electrocardiographic alterations include gradual deterioration of the cardiac rhythm normal patterns and arrhythmia, which may develop to multiform ventricular tachycardia (5,16,17). According to Eubig (12), the most common electrocardiographic findings in dogs exposed to bufotoxin are sinus tachycardia and normal sinus rhythm.…”

Intoxicação por veneno de sapo em um canino

“…Como mecanismo de defesa contra seus predadores, o sapo do gênero Bufo possui glândulas paratóides localizadas na região posterior à órbita ocular que produzem e estocam um líquido mucoso e esbranquiçado (SAKATE & OLIVEIRA, 2000). Os cães atacam os sapos causando a compressão das glândulas com conseqüente eliminação do veneno, que entrará em contato com a mucosa oral e pele não integra.…”

“…Os animais podem apresentar sinais nervoso, incluindo convulsões, ataxia, nistagmo, opistótomo, estupor e coma (ROBERTS et al, 2000). A morte destes cães está relacionada ao efeito cardiotóxico do veneno levando à morte por fibrilação ventricular (OSWEILER, 1995;SAKATE & OLIVEIRA, 2000). A manifestação dos sinais clínicos se dá rapidamente após a intoxicação, sendo que a morte pode ocorrer 15 minutos após o aparecimento dos sinais clínicos (SAKATE & OLIVEIRA, 2001).…”