First reports of envenoming by South American water snakes Helicops angulatus and Hydrops triangularis from Bolivian Amazon: A one-year prospective study of non-front-fanged colubroid snakebites

Abstract

Although snakebite incidence is underestimated in Bolivia, the Amazon region presents the highest incidence of these accidents. The local effects of bites by some non-front-fanged colubroid (NFFC) snakes are usually confused with that of viperids, resulting in the improper use of antivenoms and medications. Since there is scarce information on clinical treatment and management of NFFC bites from Bolivian Amazon, we conducted a prospective study of NFFC snakebites by reviewing the records of patients admitted with a snakebite diagnosis at Hospital Central Ivirgarzama, Bolivia. Snakebites were recorded for 12 months (December 2019–November 2020), including information about the sex and age of the patient, snakebite date, and treatment. Eight (5.7 %) of 152 patients were bitten by NFFC Helicops angulatus, Hydrops triangularis, and Erythrolamprus sp. Our results showed that 5/7 patients had prolonged clotting time and INR, as well as local edema and mild pain, suggesting systemic envenoming. Previously non-documented mild coagulopathy was observed for H. angulatus and H. triangularis bites. In some cases, incorrect first-aid measures, and inappropriate use of bothropic/lachesic antivenom were administrated. All the patients received supportive therapy and antihistamine drugs. Unsupported use of non-evidence-based treatments for snakebites such as corticoids, non-steroidal anti-inflammatory drugs (NSAIDs), and prophylactic antibiotic prescription were recorded. In conclusion, we describe the first formally documented snakebite cases produced by NFFC from Bolivia, highlighting the urgent need for training of the medical team in the snake identification, clinical management of snakebite, and the existence of a human-snake conflict involving NFFC species.