Most of the world’s approximately 3,000 snake species are nonvenomous and only 200 are considered by the World Health Organization to be medically significant venomous species. However, snakebite fatalities are common occurrences in many parts of the world. According to a 2008 study published in PLoS Medicine, an estimated 20,000 human deaths occur each year from snakebites, mostly in sub-Saharan Africa and Asia, though with the unreported incidents the total may be as high as 94,000.
A truly accurate count of deaths from snakebites is impossible to determine due to several factors. A large percentage of the world's venomous snakes inhabit areas, like the rural tropics, where prompt medical care is not readily available and documentation is not adequate. In these areas widespread epidemiological studies may also be lacking. All of these factors together lead to underreporting of snakebite fatalities, which must then be estimated using the documentation that is available to scientists.
Despite the relative abundance of venomous species, few deaths attributed to snakebites occur in the United States and none are reported in Canada, partially because of access to appropriate medical care. According to the Centers for Disease Control and Prevention, of the 7,000 to 8,000 people bitten by venomous snakes in the U.S. every year, only 5 die. Similar fatality rates hold true for Western and Central Europe, with a conservative estimate of 5 and 6, respectively. Eastern Europe had slightly more deaths with an estimated 37 per year. Despite the high number of venomous snakes in Australia, only about 2 to 4 deaths occur every year from snakebites.
The Andean region of South America, which encompasses the northwest quadrant of the continent, sees the most snakebite-related deaths in the Americas, with a lower estimate of 243. Mexico and Central America combined had an estimated 193 fatalities, and the tropical areas of the Amazon basin contribute an additional 100 deaths per year. The southern tip of South America sees just 4 snakebite fatalities per year on average. Compared with Africa and Asia, fatalities resulting from snakebites are relatively rare in Central and South America, despite accounting for nearly one fourth of all venomous snakebites worldwide.
The highest rate of snakebite fatalities by far occurs in south Asia, particularly on the Indian subcontinent, where nearly 11,000 deaths occur every year, accounting for over half of estimated snakebite deaths worldwide. Southeast Asia contributes approximately 790 deaths every year as a conservative estimate; however some more liberal estimates place this number at closer to 19,000. Poor, rural areas that lack appropriate medical care and the correct antivenoms contribute to this high number of snakebite fatalities, and the World Health Organization considers snakebites to be a threat to public health in these areas.
Though North Africa and the Middle East have relatively few snakebite fatalities-- 43 per year -- sub-Saharan Africa is a substantial contributor to snakebite fatality rates worldwide. An estimated 3,529 people die every year, though this is a conservative estimate; more liberal estimates suggest that this number of fatalities could be as high as 33,000. As with Asia, underreporting is an issue throughout Africa, due primarily to a lack of data detailing snakebite prevalence and the rural areas in which snakebites tend to occur.
- PLoS Medicine: The Global Burden of Snakebite: A Literature Analysis and Modelling Based on Regional Estimates of Envenoming and Deaths
- Centers for Disease Control and Prevention: Venomous Snakes
- World Health Organization: Snakebite
- PLoS Medicine: Confronting the Neglected Problem of Snake Bite Envenoming: The Need for a Global Partnership
- Australian Venom Research Unit: Snake Bite
- Tom Brakefield/Stockbyte/Getty Images