Snake bites in the Municipality of Valença, Rio de Janeiro, Brazil: possible emergence of envenoming by rattlesnake

Abstract

The state of Rio de Janeiro recorded around 500 notified cases of bites by venomous snakes each year. Accidents by rattlesnake are rare, representing less than 3% of the total. The municipality of Valença, located in the southern of Rio de Janeiro State, showed an increase in the number of accidents by rattlesnake in recent years. Data presented here were collected from the registry of emergency and medical records of patients treated at the Hospital of the Medical School of Valença in the period from January 2003 to July 2010. In this period there were 97 accidents with venomous
snakes, by Bothrops 49 (50.5%) and by Crotalus 48 (49.5%). After 2005, there was an increase in accidents by rattlesnake reaching 70% in 2009. As to origin, 81% occurred in rural areas. There was a predominance of males aged 15 to 44 years old. Most accidents by Bothrops were classified as mild or moderate and by the genus Crotalus as moderate or severe. The number of hospitalizations was higher in the genus Bothrops. Although we have not recorded any deaths, there is a risk of increased fatalities since accidents for rattlesnake have a higher mortality. Recent data demonstrate the occurrence of accidents with Crotalus durissus in other municipalities in Southern state, which makes us conclude that this snake continues to spread, serving as a warning and a need for epidemiological surveillance of the state and affected municipalities.