Snakes and snakebite envenoming in Northern Tanzania: a neglected tropical health problem

BACKGROUND: Snakebites cause considerable human and livestock injuries as well as deaths worldwide, and particularly have a high impact in sub-Saharan Africa. Generating a basic platform of information on the characteristics of snakes and snakebites in various countries is relevant for designing and implementing public health interventions. METHODS: This study was performed to identify types of snakes and some of the characteristics of snakebite cases in two communities, an agricultural and a pastoralist, in Arusha region, northern Tanzania. A total of 30 field visits were carried out in areas considered by local inhabitants to be potential microhabitats for snakes. Direct observation of snake types based on morphological features and a structured questionnaire were employed for data collection. RESULTS: A total of 25 live and 14 dead snakes were encountered. Among the dead ones, the following species were identified: two black-necked spitting cobras (Naja nigricollis); five puff adders (Bitis arietans), one common egg-eater (Dasypeltis scabra); two rufous-beaked snakes (Ramphiophis rostratus); two brown house snakes (Lamprophis fuliginosus); one Kenyan sand boa (Eryx colubrinus), and one black mamba (Dendroaspis polylepis). The frequency of snake encounters was significantly higher (χ(2) = 4.6; p = 0.03) in the pastoral than in the agricultural area; there were more snakebite cases in the former, but the differences were not statistically significant (p = 0.7). A total of 242 snakebite victims attended at the Meserani Clinic, located in the study area, between the years 2007 to 2012. Of all cases, 146 (61.6 %) and 96 (38.4 %) were male and female patients, respectively. As for age distribution, 59.1 % of snakebite victims were from the economically active age groups between 15 and 55 years. CONCLUSION: Snakebites are a threat to rural communities and public health in general. The burden of snakebites in Tanzania presents an epidemiologically similar picture to other tropical countries. Livestock keeping and agriculture are the major economic activities associated with snakebites. Community-based public education is required to create awareness on venomous snakes and predisposing factors to snakebites. These tasks demand integration of diverse stakeholders to achieve a common goal of reducing the impact of human suffering from these envenomings in Tanzania.