Epidemiology of snakebites in Europe: a systematic review of the literature

Abstract

Snakebites are rare medical emergency cases in Europe but may sometimes be severe and lead to complications. A better knowledge of snakebite epidemiology may help health authorities to better understand therapeutic requirements, especially concerning antivenoms, and thus improve treatment of snakebite. An extensive literature search for studies and articles published between 1970 and 2010 was performed. Both indexed and non-indexed articles were examined, the analysis of which took into account the heterogeneity between the studies and weighted the studies according to size of the study population covered. Most of the articles involved hospitalized patients who represented more than 90% of snakebites. Incidence, mortality and population at risk were estimated after stratification into three regions (northern, central and southern Europe) based both on viper species distribution and climatic characteristics. There was no significant variation in incidence from the north to the south of Europe. In the whole of Europe, including European Russia and Turkey, the annual number of snakebite cases was estimated at 7992 [CI 95% = 6860-9178] bites, out of which approximately 15% were considered severe (grade 3). These bites usually occurred between May and September, with a more dispersed distribution in southern Europe. The average number of deaths per annum was 4 [0.7-7.7]. Children and male victims are more affected, contrary to what one would expect given their respective proportion in the entire population. Both upper and lower limb bites were recorded at an equal frequency while the bites in other parts of the body were very rare. Immunotherapy was prescribed in one out of three snakebites in Europe, with a very high geographical variability, in spite of excellent tolerance, at least considering highly-purified immunoglobulin fragments. Snakebites are uncommon in Europe but can cause life-threatening envenomation. Fragments of highly-purified immunoglobulins are now very well tolerated and dramatically reduce both severity and mortality of snakebites when used in treatment.