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

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.