CAUSES OF DEATHS IN SNAKE BITES IN BRAZIL

FRANÇA, F.O.S.(1)

(1)Medical doctor of the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil and Hospital das Clínicas, Faculty of Medicine, University of São Paulo, Brazil.

The National Program for Surveillance and Control of Snake Bites in Brazil indicates that 20,000 accidents occur yearly (incidence rate = 15 accidents/100,000 population per year) with more than 100 deaths per year. Bothrops genus causes almost 90% of accidents, followed by Crotalus (8%), Micrurus(1%) and Lachesis (1%). The  overall case-fatality rate is 0.4% but varies according to the genus of snake, ranging from 0.4% for Bothrops to 2.5% for Crotalus envenoming. To determine the causes of death we have to know continuously where this accidents occur and the epidemiological, clinical and therapeutic data to characterize the real situation of this health problem in our country. But unfortunately we do not know the cause of death in the majority of this cases. Researchers has related many factors that can affect the prognosis of snakes accidents. Many variables probably has influence on snake bites severity. Basically, we can divide this factors in three groups: 1) Epidemiological: Time between bite and treatment: patients who had received treatment after 6 hours after the bite, presents an important risk factor for severity of envenoming; Use of tourniquet: increase the probability of local complications, including local infections that could progress to septicemia; Site of bite: face and intravascular are more severe; Patient’s age: patients aged with less than 7 and more than 70 years presents, in general, major chance to develop complications; Length of snake: adult snakes could cause more commonly severe cases; 2.) Clinical: Probably almost all deaths by Bothrops and Lachesis occurs in consequence of acute renal failure, massive hemorrhage, shock and septicemia. In Crotalus and Micrurus accidents the presence of signs of respiratory distress and in Crotalus the presence of renal failure define the severity; 3) The quality of treatment: Correct evaluation of the severity in the admission; Use the especific antivenom in adequate dosage intravenously; Precocity in detection and treatment the complications in severe envenoming and; Transference to ITU in severe cases.

Finally, in order to contribute to decrease the lethality of snake bites we have to keep continuous up dating of the national data, maintain and increase the decentralization of distribution of the antivenom, references services to treat severe cases, improve the systematic training of the health care workers, disseminate information on prevention and first aid after snake bites to the population and stimulate the research to improve the treatment.

CORRESPONDENCE TO:

FRANÇA, F.O.S., Hospital Vital Brazil, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo, 05503-900, SP, Brasil, Email: fosfranca@uol.com.br