Epidemiological and clinical aspects of snakebites in the upper Juruá River region, western Brazilian Amazonia

Abstract

This study addresses the clinical and epidemiological aspects of envenoming cases resulting from snakebites treated at a hospital in Cruzeiro do Sul, in the upper Juruá River region, western Brazilian Amazonia. The specific identity of snakes that caused the envenomings was inferred (a) from the diagnosis of patient symptoms and signs upon hospital admission, (b) by enzyme immunoassay for detection of Bothrops atrox and Lachesis muta venom from serum samples taken from patients before antivenom therapy, or (c) by direct identification of the snake, when it was brought along to the hospital or photographed. There were 133 snakebites (76.2 cases per 100,000 inhabitants) registered during one year (July 2017 to June 2018). Most snakebites (88.7%) were caused by Bothrops spp., and the rest by non-venomous snakes or dry bites. Snakebites tended to occur more often during the rainy season, coinciding with the period of greater reproductive activity of the snakes and greater availability of their prey. In addition, the increase in the water level of rivers and lakes during the rainy season tends to concentrate snakes in dry places and, thus, to increase encounters with humans. Information campaigns on prevention and first aid, specially among the most vulnerable groups (indigenous people, farmers, and children and teenagers in rural areas), and the importance of using protective equipment (boots, leggings, leather gloves) in certain high risk activities (e.g. agriculture and extractivism in forests) are fundamental for the reduction of snakebite morbidity.

Bleeding Disorders in Bothrops atrox Envenomations in the Brazilian Amazon: Participation of Hemostatic Factors and the Impact of Tissue Factor

“…B. atrox is responsible for 80-90% of snakebites in the Brazilian Amazon [18,28]. Despite the similarities between the toxins from the B. atrox and B. jararaca venoms [6,26], in our study, we observed that 20.0% (20/100) of B. atrox snakebite patients in the western Brazilian Amazon present systemic bleeding, while 46.1% of B. jararaca snakebite patients present this manifestation [27].…”

Pan-American Lancehead Pit-Vipers: Coagulotoxic Venom Effects and Antivenom Neutralisation of Bothrops asper and B. atrox Geographical Variants

“…Epidemiological data suggest that across South America, 70-96.6% of envenomings are inflicted by the Bothrops species [3][4][5][6]. Most of these bites are from B. atrox in Amazon regions [6,7] or B. asper in northern South America [8]. Similar values are also reported across Central America, with 50-80% of all snakebites attributed to B. asper [8,9].…”

“…Bothrops is a genus of pit-viper-commonly known as lanceheads-that is distributed across South and Central America, as well as Mexico. Epidemiological data suggest that across South America, 70-96.6% of envenomings are inflicted by the Bothrops species [3][4][5][6]. Most of these bites are from B. atrox in Amazon regions [6,7] or B. asper in northern South America [8].…”

A brief review on the natural history, venomics and the medical importance of bushmaster (Lachesis) pit viper snakes

“…Only in the breeding season, males are on day alert and ready for combat. In addition, venom lethality is weak compared to those of some other vipers ( Bolaños, 1972 ; da Silva et al, 2020 ). Brown (1973) quote the following LD50 values of L. m. muta venom for mice: 1.5 mg/kg (intravenous), 1.6–6.2 mg/kg (intraperitoneal) and 6.0 mg/kg (subcutaneous).…”