Human, snake, and environmental factors in human-snake conflict in North Bihar — a one-year descriptive study

Abstract

Background: The state of Bihar has the third largest number of snakebite deaths in India. The purpose of this study is to explore the factors related to human-snake conflicts in northwest Bihar and southern Nepal. Using these findings, various strategies were proposed to reduce the incidence of snakebites. Method: Data were collected from 609 patients at Duncan Hospital in Raxaul, Bihar, India between 1 July 2012 and 30 June 2013. Patients were included if they had a history of snakebite or unknown bites. Patients with symptoms of envenomation but no known bites were also included, as were patients who were dead on arrival due to a snakebite. Results: The 10-19 year old age group is the peak age group (28.4%) for snakebite. There is a slight preponderance of males (52.7%). 51.4% of bites occurred on the foot/ankle. The envenomation rate was 12.6%. The mortality rate of those envenomed that arrived at the hospital alive was 6.3%. Fourteen people were dead on arrival at the hospital. 75% of people were unable to identify what, or what type of snake, bit them. Common Wolf Snakes (Lycodon aulicus) were the most common snakes brought to the hospital, followed by Spectacled Cobra (Naja naja). Patients who brought snakes to the hospital and attempted identification were all successful at identifying cobras, but all those who brought in Common Wolf Snakes incorrectly identified them as Kraits. The highest monthly frequency of snakebites occurred between June and September; while on a daily basis, the highest frequency occurred between 1700hrs-2200hrs, the time in which 39.1% of all bites occurred. 59.2% of the bites occurred in and around the house. Farming, housework, sleeping, playing, and toileting in fields were the activities most commonly occurring when bitten. Sleeping on the floor increased the risk of envenomation [OR= 5.8, 95%CI 1.8-18.6], while sleeping under a mosquito net decreased the risk of envenomation [OR= 0.17, 95%CI 0.04-0.6]. Conclusion: Snakebite is a rural hazard in Northern Bihar, not just an occupational hazard. Use of toilets and sleeping on beds with well tucked in mosquito nets may help prevent snakebites. Education to reduce the risk of snakebites should begin in childhood and be regularly reinforced prior to the rainy season. Prevention measures should include environmental management such as keeping eating areas clean and keeping food storage and sleeping areas a distance apart.