Future of snakebite risk in India: Consequence of climate change and the shifting habitats of the big four species in next five decades

Background: Climate change is anticipated to significantly impact the biogeographic distribution of snakes, leading to notable shifts in their habitats toward anthropogenic landscapes. This may potentially increase the incidence of Big Four species (Bungarus caeruleus, Daboia russelii, Echis carinatus, and Naja naja) envenomation, a notable human-health risk that has not yet been assessed in India being the most affected country in South Asia. Therefore, this study integrates species distributions with socioeconomic and healthcare data to prioritize areas for targeted interventions to mitigate the envenomation risks effectively in India. Methodology/Principal findings: The present study employed ensemble species distribution models (SDMs) to analyze the geographical distribution of the Big Four species under current climatic conditions and projected these models to estimate potential species distributions up to 2080. Furthermore, by incorporating various future climatic scenarios, the study assessed the potential loss and gain of suitable habitats along with their overlap with cropland and built-up areas. Further, integrating SDMs with socioeconomic scenarios and present health infrastructure, the study developed a risk index to estimate the current and upcoming vulnerable districts and states in next five decades. The results indicate significant losses in potentially suitable habitats for the Big Four species under future climatic scenarios. However, the risk index identified several southern Indian states and districts, such as Karnataka (Chikkaballapura, Haveri, and Chitradurga etc.) and Gujarat (Devbhumi Dwarka and Jamnagar etc.), as having high vulnerability to snakebite. Additionally, under climate change scenarios, many northern and northeastern states and districts, including Assam (Nagaon, Morigaon, and Golaghat etc.), Manipur (Tengnoupal), and Rajasthan (Pratapgarh), have experienced an increased risk of snakebite, presenting a significant public health concern in these regions. Conclusion/Significance: The integrated risk index indicates that the southwestern region urgently needs priority attention to combat fatalities from envenomation by the Big Four species, while also highlighting the future needs of the northern and northeastern region to aid public health efforts. To mitigate these impacts, local governments and international communities must intensify efforts to counter climate change and protect vulnerable regions from Big Four envenomation. Author summary: Snake envenomation is a critical public health issue in India, disproportionately affecting economically deprived populations. India records the highest number of snakebite fatalities worldwide, primarily due to the Big Four species. While previous research has focused on reducing snakebite-related deaths, little has been done to integrate species distribution with socioeconomic factors, anthropogenic landscape, and healthcare infrastructure to assess district-level risks in India. This study is the first to predict the impact of climate change on the distribution of the Big Four species while identifying regions most at risk. The research incorporates socioeconomic data and healthcare infrastructure to prioritize regions for medical intervention now and in the future. Addressing this emerging threat will require coordinated efforts from government authorities, regional health organizations, and the international community to effectively manage snake envenomation as a neglected tropical disease (NTD) in India.