Snakebite envenoming is a potentially fatal but largely hidden public health crisis, especially in poor, rural communities in tropical and subtropical regions. Researchers reviewing data from 79 countries estimate that at least 2.1 million people are poisoned by snake venom each year, with the true figure potentially reaching 7 million. Annual deaths may range from 274,000 to 513,000, and sub-Saharan Africa appears to bear the greatest burden.
Not every snakebite injects venom. When venom enters the body, however, it can cause serious illness or death. In rural areas of sub-Saharan Africa and South Asia, many victims live hours from the nearest clinic, lack transportation, or seek help from a traditional healer. As a result, many cases are never included in national health statistics.
As researchers with decades of experience studying the epidemiology of snakebites and tropical diseases, we found that snakebite data are facing a crisis. More than half of the countries affected by venomous snakes do not know how many people are bitten or envenomed each year.
To address this gap, we conducted a study mapping the global burden of snakebite envenoming and associated deaths. We reviewed studies from 79 countries published up to March 31, 2025, updating findings from the 2008 Global Burden of Disease study.
For areas where evidence remained limited, we built a geostatistical model combining available real-world data with environmental and socioeconomic factors. This allowed us to estimate envenoming and mortality rates even where official records were incomplete.
Our findings indicate that snakebite envenoming is a much larger public health crisis than official statistics suggest. Sub-Saharan Africa is the hardest-hit region, while the World Health Organization has set a goal of halving snakebite-related mortality and disability by 2030. Mapping the problem at country level is an important first step toward reaching that goal.
Revealing the hidden burden
To compensate for the lack of reliable data, we used a model-based geostatistical framework. This approach combines known data points with environmental signals to estimate patterns that are not directly observed.
Rather than assuming that every region has the same risk, the model uses statistical probabilities to calculate a range of expected outcomes based on factors such as climate, snake species abundance, and socioeconomic conditions. It can estimate the probability of a snakebite in a particular location even when official health records contain no cases.
We compared hospital reports and local statistics with community survey data collected on the ground. This helped us account for underreported envenoming and establish both lower and upper estimates for snakebite cases and deaths.
We estimate that at least 2.1 million people worldwide experience snakebite envenoming each year. The actual number could be as high as 7 million. After adjusting for substantial underreporting, annual deaths could range from 274,000 to 513,000.
The burden is unevenly distributed. Sub-Saharan Africa alone accounts for 45% of global envenomings and deaths, and its burden has probably been underestimated for decades. People in the region experience snakebite envenoming and death at nearly three times the rate observed in South Asia.
Countries including Nigeria, the Democratic Republic of the Congo, and Ethiopia are among those with a heavy burden, driven by large rural populations and high exposure among agricultural workers.
Why sub-Saharan Africa is hardest hit
Sub-Saharan Africa’s disproportionate burden is rooted in structural conditions rather than chance.
The continent has a wide range of medically important venomous species, including saw-scaled vipers (Echis spp.), puff adders (Bitis arietans), African cobras (Naja spp.), and mambas (Dendroaspis spp.). These snakes cause substantial illness and death across the region.
Millions of rural agricultural workers also work in fields without protective footwear and walk along unlit paths at night. After a bite, a treatable medical emergency can quickly become fatal because of weak health systems, long journeys to healthcare facilities, high treatment costs, or a complete lack of effective antivenom. Similar conditions exist in parts of Asia.
We estimate that more than 800,000 survivors are left with long-term disabilities each year, including amputations and other permanent impairments. These consequences can reduce household incomes, increase medical costs, and push already vulnerable farming families further into poverty.
Using data to guide the response
Meeting the World Health Organization’s goals will require moving beyond guesswork and using spatial risk data to guide policy.
By identifying high-risk areas, governments and global health partners can stockpile antivenoms where they are most needed, train primary healthcare workers in high-burden rural communities, and improve rapid transportation to medical facilities.
Snakebite envenoming has remained hidden for too long. Better data will not solve the problem on its own, but it can help ensure that antivenoms, healthcare services, and prevention efforts reach the communities that need them most.
Source: www.sciencedaily.com