Epidemiology of Schistosoma mansoni, Snail Intermediate Host Fauna and Physico Chemical Characterizations of Snail Breeding Habitats in Mizan Aman, Bench Sheko Zone, Southwest, Ethiopia.

Abstract

Background: Schistosomiasis is snail borne parasitic neglected tropical disease which causes major public health problem and poses a negative economic development in Africa. In Ethiopia numerous studies reported that prevalence of Schistosoma mansoni (S. mansoni) infection was high and the distributions, type of snail intermediate host responsible for transmission and hot spot areas are not well documented. The purpose of this study was to determine the prevalence of S. mansoni infection, determination and distribution of snail intermediate host fauna, hot spot transmission area and physico chemical characterization of snail breeding habitats in Mizan Aman, Bench Sheko Zone, South west Ethiopia. Method: A community based cross sectional study was conducted on 364 household’s selected using systematic sampling technique from October 2021 - February, 2022. Stool sample collected from each study participant and examined by Kato-katz technique within 24hours. Snails were collected by scoop net, gloved hand and transported by plastic container containing old water and vegetation to Mizan Aman public health regional laboratory for morphological identification and examination of cercariae shedding and snail infection. Water physico-chemical parameters were characterized on site and in the laboratory, from each snail sampling sites. Data were entered into EPI Data version 3.1 and analysis was carried out by SPSS version 20. Descriptive analysis was conducted and for risk factors and physico chemical parameters, P-value <0.05 were reported as statically significant. Results: The overall prevalence of S. mansoni infection was 23.2% (95% CI: 18.9-28), with 80.3, 16% and 3.7% of light, moderate and heavy infection intensity, respectively. Using river water for domestic use, swimming, bathing habit in river and presence of farm close to river were risk factors. A total of 274 snails were collected, of which Biomphalaria pfeifferi, Biomphalaria sudanica, and Lymnaea natalensis accounted for 187(68.2%), 29(10.6%), and 58(21.2%), respectively. The pooled prevalence of cercariae infection was 34(12.4%). Turbidity and conductivity had significant association with snail abundance. Conclusion: Schistosoma mansoni infection is an ongoing public health problem in Mizan Aman, Bench Sheko Zone, South west Ethiopia. Biomphalaria pfeifferi snail species are the major intermediate host of schistosome responsible for transmission to human. All snail sampling sites except Shonga-1 was infested with one or more types of cercariae. Therefore, integrated control strategy should be followed to attain morbidity control.