# Snakebite patterns in rural Sri Lanka and their implications for preventive measures

## TL;DR

This study examines snakebite patterns in rural Sri Lanka to suggest prevention strategies like protective footwear and safer sleeping environments.

## Contribution

The study identifies specific snakebite patterns and proposes targeted prevention measures based on detailed epidemiological data.

## Key findings

- Protective footwear could prevent 83% of Russell’s viper bites and 52% of hump-nosed viper bites.
- Safer sleeping environments could prevent 59% of Indian krait bites.
- Most bites occurred during the rainy season and in domestic gardens or farmlands.

## Abstract

Snakebite prevention is often neglected despite snake envenoming being a major problem in the rural tropics. We aimed to describe the epidemiology of snakebites in rural Sri Lanka to identify potential focused preventative strategies.

The Anuradhapura Snakebite Cohort prospectively recruits snakebites admitted to the Teaching Hospital, Anuradhapura, in Sri Lanka. Epidemiological data on all snakebites from August 2013 to October 2014 and May 2017 to January 2023 were extracted.

There were 4708 snakebites, and 2202 were authenticated by specimen identification or serum analysis using enzyme-linked immunosorbent assay [H. hypnale, 988 (44·6%), D. russelii, 737 (33·3%), B. caeruleus, 101 (4·6%), N. naja, 62 (2·8%)]. Median age was 42y (IQR:29-54y), and 3027 were male (64·6%). There were 1659 (37·5%) snakebites in domestic gardens, 1153 (26·0%) on farmland, and 870 (19·6%) indoors. 3642/4620 (78·8%) were lower-limb bites, mainly the foot (3273; 70·9%). 1435/4671 (30·7%) occurred between 6 and 9 pm. Increased numbers of bites were reported from September to February. Of 988 H. hypnale bites, 781 (82·1%) occurred outdoors, 493 (51·8%) on the foot, and 252 (26·2%) on the hand. 704 (73·0%) H. hypnale bites occurred at home, and on the hand while cleaning the surrounding environment and collecting firewood. Of 721 D. russelii bites, 643 (89·2%) occurred on the foot, 310 (43·0%) on farmland and 286 (39·7%) outdoors. Of the 101 B. caeruleus bites, 75 (74·3%) occurred at night, and sixty (60·6%) while victims slept. Of 62 N. naja bites, 53 (85·5%) occurred during the day and 37 (59·7%) outdoors.

We identified epidemiological findings that indicate possible avenues for prevention. Protective footwear would prevent outdoor bites, including 83% D. russelii bites and 52% H. hypnale bites. Long-handled tools would prevent H. hypnale bites to the hands, and safer sleeping environments would prevent B. caeruleus bites.

Snakebite is a significant, yet often neglected, public health issue. A higher number of snakebites is reported from rural Sri Lanka. We aimed to describe patterns of snakes in rural Sri Lanka and identify potential ways to prevent snakebites in the region. We looked at data from over 4,700 snakebite patients admitted to a major hospital in rural Sri Lanka from 2013 to identify the snakebite patterns related to highly venomous snakes in the region: Russell’s viper, hump-nosed viper, Indian krait, and common cobra. Most identified snakebites were hump-nosed viper bites and Russell’s viper bites. The highest number of bites occurred during the rainy season and during dusk and early night. Hump-nosed viper bites mainly occurred on feet and hands in domestic gardens while cleaning and collecting firewood. Russell’s viper bites were mainly reported in farmlands and involved the feet. Most Indian krait bites occurred late at night while victims were sleeping. Wearing protective footwear could potentially prevent 83% of Russell’s viper bites, half of hump-nosed pit viper bites, and 40% of common cobra bites. Maintaining safer sleeping environments, such as using mosquito nets, sleeping above ground level, would prevent 59% of Indian krait bites. Our findings suggest that snakebite burden in rural areas can be significantly reduced through the application of simple measures.