A Cross Sectional Assessment on Distribution of Snail and Risk Factors of Schistosoma Mansoni Infection in Proximity to Water Contact Points in Gorgora Town, Western Dembia District, Northwest Ethiopia.

Abstract Background: Schistosomiasis is one of the great neglected tropical diseases with socio-economic and health problem worldwide. In Ethiopia numerous studies reported S. mansoni is high among school-age and preschool age children. Though intensive prevalence studies are conducted the snail distribution and infectivity status and human infection rate dynamics in Ethiopian context remains poorly understood. Thus the purpose of the current study was to assess distribution of snail and risk factors of Schistosoma mansoni infection in proximity to water contact points in Gorgora town, Western Dembia District, Northwest Ethiopia. Method: A Community based cross-sectional study was conducted in Gorgora Town from March to May 2020. A total of 385 study participants were selected by systematic random sampling technique. Stool sample was collected and examined by Kato-Katz technique. Malacological survey was done from sampling sites showing signs of human activity near Lake Tana shoreline. Live snails collected in plastic bucket containing water and weed were transported within four hours to the University of Gondar, Medical parasitology laboratory for identification and determination of infection. Data was entered with EPI Data version 4.4.2.1. Data analysis was carried out using SPSS version 20.0 and STATA version 15.0. p-value ≤ 0.05 was reported as statistically significant. Spatial distribution analysis was done using ArcGIS system for Geographical Information System (GIS). Result: The overall prevalence of S. mansoni infection was 36.6% (CI: 32-41.9) with intensity of 30.5%, 27.0% and 42.6% for light, moderate, and heavy, respectively. Among the different fresh water snails collected on the basis of shell morphology 546(%) were Biomphalaria pfeifferi, 310(28.1%) were Bulinus spp, 101(9.1%) were Lymnaea, and 147(13.3%) were Bivalve. Schistosome infection in Biomphalaria spp. was 0.0%. Swimming frequency and proximity to water body were observed to be the most associated risk factor to S. mansoni infection. Conclusion: The study showed that S. mansoni is an ongoing health problem in Gorgora. Different fresh water snails with a potential of transmitting diseases of human and veterinary importance that requires attention had been identified. Longitudinal and molecular study on Biomphalaria pfeifferi infection rate as well as susceptibility to schistosome infection is recommended.