Epidemiology of snakebites in Kédougou region (eastern Senegal): comparison of various methods for assessment of incidence and mortality

Abstract

BackgroundAlthough considered a public health issue in Senegal, the actual incidence and mortality from snakebite are not known. In the present study, an epidemiological survey was carried out in Kédougou region, southeastern Senegal, where envenomations, particularly by Echisocellatus, are frequent and severe.MethodsThree sources of data were used: records from health centers and reports by health professionals; traditional healers; and household surveys.ResultsThe annual incidence and mortality provided by health centers were 24.4 envenomations and 0.24 deaths per 100,000 population, respectively. The annual incidence recorded by traditional healers was 250 bites per 100,000 inhabitants, but the number of deaths was unknown. Finally, the household surveys reported an annual incidence of 92.8 bites per 100,000 inhabitants and an annual mortality rate of 2.2 deaths per 100,000 inhabitants. The differences in incidence and mortality between the different methods were explained by significant bias, resulting in particular from the complex patient’s healthcare-seeking behavior. The incidence provided by health records should be used to specify the immediate quantitative requirements of antivenoms and places where they should be available first.ConclusionMandatory reporting of cases would improve the management of envenomation by simplifying epidemiological surveys. Patients’ preference for traditional medicine should prompt health authorities to urge traditional healers to refer patients to health centers according to defined clinical criteria (mainly edema and bleeding or neurotoxic symptoms). Finally, household surveys were likely to reflect the actual epidemiological situation. Poison Control Center of Senegal should continue its work to sensitize stakeholders and train health staff.

Epidemiology, ecology and human perceptions of snakebites in a savanna community of northern Ghana

“…The human deprivation, psychosocial despair, and loss of income resulting from snakebite morbidity and mortality [7, 35, 40], are clearly demonstrated by our complementary data from the northern part of the savanna zone in Ghana, where annual snakebite burdens are the most severe across the entire country. Our data also indicate that the vast majority of snakebites are never reported to conventional medical treatment facilities but managed by TMPs, home treatment or are untreated, sometimes with fatal consequences [16, 24, 43]. Long delays in antivenom treatment often lead to severe cases of morbidity (e.g.…”

“…2). Based on hospital records, the whole district therefore probably has a burden of at least 50 reported cases yearly, and probably as much as double if the reporting percentage is up to 50% as estimated in similar studies [12, 16, 41]. Our upper-lower limits of annual snakebite envenomations during the 10-year period therefore range from 100-750, equivalent to 75-575 per 100,000 inhabitants, with a mortality rate of 2-17 per 100,000.…”

“…Previous epidemiological studies have largely been limited to short-term data series with lower sample sizes of predominantly retrospective hospital records for Ghana [22, 23, 24] and sub-Saharan Africa [25, 26, 27, 28, 29], where complementary or nationwide long-term published studies remain scarce [1, 16, 30, 31]. Estimates of regional or national snakebite burdens based exclusively on hospital records inevitably neglect many snakebite cases treated at home or by TMPs [1, 4, 16, 30]. In contrast, our study provided a rare opportunity to test consistencies in epidemiological baseline information gathered from different sections of a typical rural savanna community in West Africa [16], regarding general demography and human-snake conflict, as well as snake toxicology and ecology.…”

“…As the Savelugu-Nanton District road network was fairly well developed during our study, we attribute the high patronage of TMPs mainly to low educational level and income, limited access to orthodox medical facilities as well as high costs or lack of sufficient and effective antivenom administration. This TMP-seeking behaviour is widespread in Asia [33] and Africa [16, 34, 35, 36] where herbal extracts of diverse medicinal plant assemblages [37] are often either culturally preferred or are the only affordable or alternative therapeutic treatment available among low-income rural communities with high levels of illiteracy and strong belief in the supernatural [16, 19, 38, 39, 40, 41].…”

Priority Actions and Progress to Substantially and Sustainably Reduce the Mortality, Morbidity and Socioeconomic Burden of Tropical Snakebite

“…Data from studies conducted in India [11,14], Bangladesh [15], Sri Lanka [16,17], Nigeria [12,18], Burkina Faso [19], Kenya [20] and Senegal [21], amongst others, provide evidence of an increasing capability of acquiring snakebite epidemiology data that need to be adopted and promoted more widely. The workshop was informed of hospital-based and community survey projects being undertaken or planned in several countries represented by the recently established African Society of Venimology and in Southeast Asia.…”