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.
