Risk of snakebites is increasing as reptiles adapt to a changing world, WHO-backed study finds

The Nature Communications study, conducted at the London School of Hygiene & Tropical Medicine, finds that global warming and habitat loss are systematically shifting snakes' living ranges. Built on a database covering 209 species, the central model estimates a 25 per cent rise in snakebite cases by 2030.

The World Health Organization (WHO) added snakebite envenoming to its "neglected tropical disease" list in 2017. Each year, 5.4 million people are bitten by snakes; between 81,000 and 138,000 die, and 400,000 sustain permanent disability (WHO 2024 data). The study argues this present total is rising in proportion to climate forcing.

The model's parameters: at 1.5°C warming, average snake habitat expansion shifts 230 km north in the tropical belt and 180 km north in the temperate belt. In India, 18 per cent of the population currently experiences a snakebite event in their lifetime; that figure reaches 23 per cent in the 2030 model output. In sub-Saharan Africa, particularly Ethiopia, Kenya and Nigeria, the model forecasts a 35 per cent increase.

Lead author Professor Anna Pintor told the Guardian: "Snakes are a marked adaptation signal for us. They do not choose people in their habitats, but their habitats are now entering human living areas." Pintor acknowledged the study's limitations: the model captures reptile behavioural adaptation with a limited parameter set, and population dynamics require a longer time-series.

The basic logic of the climate model is this: snakes are ectotherms that maintain thermoregulation through external temperature. When the temperature range widens, species shift their ranges northward or to higher elevation. Combined with habitat loss, deforestation and agricultural expansion bring species closer to rural settlement zones. The South African sub-analysis shows that the black mamba population in Limpopo province has expanded 22 per cent northward over the last 12 years.

Dr Bernadette Abela-Ridder, head of the WHO's neglected diseases department, commented on the study: "This study shows the antivenom (snake-venom antiserum) supply chain needs to be re-evaluated on a global scale. Current antivenom production centres are mainly in Australia, Brazil and India; production capacity is insufficient for 2030 demand." The WHO's antivenom access programme targets one million doses a year by 2030.

Antivenom cost and access are chronic problems in developing countries. In Kenya, the price of one dose of Echitab-Plus antivenom ranges from USD 50 to 100 — a significant share of average household income. India's Polyvalent Anti-Snake Venom Serum is cheaper (USD 15-25), but rural access is uneven. Brazil distributes antivenom free through its national health system (SUS), a model the study cites as a reference.

The study built socio-economic variables into its model alongside environmental factors. Open footwear use, agricultural workers' night hours and education level all raise snakebite risk. In Türkiye, snakebites total around 1,500 cases annually; the bulk are in the Mediterranean and South-East Anatolia regions, with the most common species being the nose-horned and Ottoman vipers (Vipera ammodytes and V. xanthina). Ministry of Health hospital records put the mortality rate at 1-2 per cent.

For development follow-up, Pintor's team plans next to release an open-data platform overlaying snake species density maps with health facility access maps. Production partners include the WHO Geneva, the Wellcome Trust, and Médecins Sans Frontières. The data is scheduled for publication in November 2026 and will serve as a reference tool for antivenom supply chain planning work.

This study on snakebites highlights a reptile-driven new vector in the climate-health linkage. Traditional climate-health literature focused on mosquito-borne diseases such as malaria, dengue and Zika; reptiles received limited treatment. The study proposes a heading that places reptiles forward for environmental health policy over the next decade: both for antivenom production capacity and for community health education programmes.

For healthcare decisions, particularly in the event of animal envenomation, go to the nearest emergency department; this article does not substitute for medical advice.