Rediscovery of severe saw-scaled viper (Echis sochureki) envenoming in the Thar desert region of Rajasthan, India

Abstract

Objectives: In India, venomous snakebite remains an enigma. Although ineffective first aid treatments that are centuries old continue to be used by people bitten by snakes, important factual information, such as the importance and uniqueness of bites by the northern saw-scaled viper (Echis sochureki), has been largely lost and forgotten. In this paper, we report the first systematically gathered data on the clinical course of envenoming by E sochureki in Rajasthan, India. Clinical information is reported on 12 victims bitten by definitively identified E sochureki, and 2 clinical cases are described in greater detail to illustrate the severity of envenoming by this snake.

Methods: A data collection form was developed and used to prospectively gather clinical information regarding patients who were bitten by E sochureki and who brought the dead snake with them to hospital. All snakes were definitively identified by an experienced herpetologist. Information on symptoms and signs, management (both first aid and hospital), and outcomes was collected.

Results: All 12 victims had evidence of systemic envenoming, including abnormal 20-minute whole blood clotting tests (with systemic bleeding in 7). All received polyvalent antivenom made, in part, with Echis carinatus venom from southern India. Antivenom was relatively ineffective in restoring coagulation to these patients. All patients survived, although 1 patient suffered an intracranial bleed with residual hemiparesis.

Conclusions: Echis sochureki causes severe bites in Rajasthan. Work needs to be done to alter the first aid practices used for snakebites in this area, to encourage more rapid presentation to hospital, and to develop antivenom that is more effective against E sochureki.