The Global Burden of Snakebite: A Literature Analysis and Modelling Based on Regional Estimates of Envenoming and Deaths

Abstract

BackgroundEnvenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Few attempts have been made to quantify the burden, and recent estimates all suffer from the lack of an objective and reproducible methodology. In an attempt to provide an accurate, up-to-date estimate of the scale of the global problem, we developed a new method to estimate the disease burden due to snakebites.Methods and FindingsThe global estimates were based on regional estimates that were, in turn, derived from data available for countries within a defined region. Three main strategies were used to obtain primary data: electronic searching for publications on snakebite, extraction of relevant country-specific mortality data from databases maintained by United Nations organizations, and identification of grey literature by discussion with key informants. Countries were grouped into 21 distinct geographic regions that are as epidemiologically homogenous as possible, in line with the Global Burden of Disease 2005 study (Global Burden Project of the World Bank). Incidence rates for envenoming were extracted from publications and used to estimate the number of envenomings for individual countries; if no data were available for a particular country, the lowest incidence rate within a neighbouring country was used. Where death registration data were reliable, reported deaths from snakebite were used; in other countries, deaths were estimated on the basis of observed mortality rates and the at-risk population. We estimate that, globally, at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite. These figures may be as high as 1,841,000 envenomings and 94,000 deaths. Based on the fact that envenoming occurs in about one in every four snakebites, between 1.2 million and 5.5 million snakebites could occur annually.ConclusionsSnakebites cause considerable morbidity and mortality worldwide. The highest burden exists in South Asia, Southeast Asia, and sub-Saharan Africa.

Bilateral parotid enlargement following snake bite: A rare sign

“…Of these bites, at least 421 000 -1 841 000 envenomations occur resulting in 20 000-94 000 deaths worldwide [1] . Bites by venomous snakes are not always accompanied with the injection of venom.…”

Medically important differences in snake venom composition are dictated by distinct postgenomic mechanisms

“…Of all venomous animals, snakes are the most wellknown because of their medical importance: As many as 90,000 people die each year as the result of snakebite, with the majority of those inhabiting rural poor regions of the tropics (2,3). This substantial mortality burden of snakebite victims is surprising because antivenom treatment (immunoglobulins from venom-immunized horses/sheep) can be highly effective at neutralizing the toxic components present in snake venom (4,5).…”

The epidemiology of envenomation via snakebite in the State of Piauí, Northeastern Brazil

“…Furthermore, rural areas are more severely affected by snakebites, and exhibit high morbidity and mortality rates, which is related to these communities' higher exposure to high-risk areas and diffi culties in accessing health centers that can provide snake antivenom. Unfortunately, the economic impact of these injuries is considerable, especially because most of the victims are young (14) , that is, they are representative of the economically active population. Table 2 shows that the largest group of victims received medical assistance within 3h after the snakebite (n = 545; 35.7%), and that 235 (15.4%) patients received treatment within the fi rst hour.…”