Comparing community and hospital data of snakebite in North Bihar: a community incidence survey and a parallel hospital-based clinical study

In Bihar, an estimated 4500 snakebite deaths occur per year, but community data are scarce. Using a multi-stage cluster design, 4159 households were interviewed across six Community Development (CD) blocks in North Bihar, identifying 206 snakebites and 254 deaths between the Chhaat festivals of 2014 and 2015. Concurrently, 357 snakebite victims presented to Duncan Hospital from this area. None of the 254 verbal autopsies were attributed to snakebite envenoming. The annual community snakebite incidence was 643/100,000 person-years (95% confidence interval [CI] = 556-730) with peak incidence in women aged 30-39 years at 1323/100,000 person-years (95% CI = 837-1809). Two-thirds of snakebite victims attended traditional healers first for help (95% CI = 59.9-73.2). The community envenomation rate was 24.9/100,000 person-years (95% CI = 7.6-42.2). The hospital envenomation rate was 4.6% (95% CI = 3.5-5.7). Of the hospital snakebite deaths, 91% (10/11) were aged <16 years. Only 4.6% (95% CI = 4.1-5.1) of snakebite victims from this area presented at the local hospital.