Identifying the biting species in snakebite by clinical features: an epidemiological tool for community surveys

Abstract

The outcome of snakebite is related to the biting species but it is often difficult to identify the biting snake, particularly in community settings. We have developed a clinical scoring system suitable for use in epidemiological surveys, with the main aim of identifying the presumed biting species in those with systemic envenoming who require treatment. The score took into account ten features relating to bites of the five medically important snakes in Sri Lanka, and an algorithm was developed applying different weightings for each feature for different species. A systematically developed artificial data set was used to fine tune the score and to develop criteria for definitive identification. The score was prospectively validated using 134 species-confirmed snakebites. It correctly differentiated the bites caused by the three snakes that commonly cause major clinical problems (Russell's viper (RV), kraits and cobra) from other snakes (hump-nosed viper (HNV) and saw-scaled viper (SSV)) with 80% sensitivity and 100% specificity. For individual species, sensitivity and specificity were, respectively: cobra 76%, 99%; kraits 85%, 99%; and RV 70%, 99%. As anticipated, the score was insensitive in the identification of bites due to HNV and SSV.

Syndromic Approach to Treatment of Snake Bite in Sri Lanka Based on Results of a Prospective National Hospital-Based Survey of Patients Envenomed by Identified Snakes

“…5,[18][19][20] Recently, Pathmeswaran and others published a clinical scoring system for identification of the snake species responsible for bites in Sri Lanka. 21 However, rather than using actual snake bite data, the authors resorted to an artificial data set based, somewhat arbitrarily, on "published literature and our knowledge from extensive clinical experience of snakebite." This set enabled them to create "as many different artificial circumstantial and clinical scenarios as possible that were both typical and atypical for bites of different species, far more than would have been possible in a real life."…”

A Profile of Snake Bites in Brazil, 2001 to 2012

“…The proportion of incidents in which the genus of the snake was unknown dropped in the whole country from 19 …”

“…Nevertheless, there is an observed tendency in the last few years of the period studied towards a reduction in the proportion of incidents reflecting an improvement in the capacity of healthcare personnel to identify the snake genus, either by mere description given by the victim, or based on the symptoms. Strategies have been developed to assist with identification, such as the establishment of protocols based on the manifested symptoms of the victim, which aid in identifying the type of poisoning and, consequently, in guaranteeing the administration of the appropriate anti-venom [5,[18][19]. Another recent strategy is, taking advantage of the advancements of information technology, which provides direct access to snakebite specialists, so that the healthcare teams could attend the victims efficiently.…”

A Study on Clinical Profile of Snakebite Victims in a Semiurban Tertiary Care Centre

“…Identification of type of snake and the time of bite plays a crucial role in determining the progression of impending complications of snakebite like neurotoxic and haemotoxic effects. (12) Administration of ASV forms the most crucial factor in effective management of snakebite victims. The National Guidelines on usage of ASV in snakebite victims is to be emphasised.…”