Scientists say snakebites are a neglected threat to public health

A new study by Sri Lanka scientists used the most comprehensive methods yet to estimate that at least 421,000 envenomings and 20,000 deaths from snakebites occur each year, especially in South and South East Asia and sub-Saharan Africa.

In order to estimate death and injury from snakebites, researcher Dr Janaka de Silva and colleagues from the University of Kelaniya conducted a systematic review of existing scientific literature and also reviewed county-specific mortality data from databases maintained by United Nations organizations.

They also identified unpublished information from Ministries of Health, National Poison Centres and snakebite experts on snakebites in countries that do not have reliable data on snakebite incidence and mortality.

This wide-ranging data retrieval process produced information for many of the world's 227 countries, which were grouped into 21 geographical regions.

Thousands of bites reported

The researchers estimate that 421,000 envenomings and 20,000 deaths occur worldwide from snakebite each year, but warn that these figures may be as high as 1,841,000 envenomings and 94,000 deaths, especially in areas of sub-Saharan Africa and South Asia where antivenoms are hard to obtain.

India has the highest estimated annual envenomings and deaths - 81,000, and 11,000 respectively.

Experts say the research is an essential step in improving accessibility of anitvenoms and the treatment of snakebite and suggest that the dire situation of antivenom availability and cost in Africa could be worsened by the current global economic crisis, where the price of a vial of antivenom is the equivalent of several months of income for most rural families.

They say better information on the global burden of snakebite would help provide an understanding of how much antivenom needs to be produced and in what areas it needs to be distributed.

Dr de Silva and colleagues conclude, despite their careful methodology, more population-based studies of incidence and mortality from snakebite are urgently needed.

The research is published in this week's PLoS Medicine.