Epidemiological study on Schistosoma mansoni infection in Sanja area, Amhara region, Ethiopia

BACKGROUND: The epidemiology of schistosomiasis is well documented and its geographic distribution has been mapped and there is an ongoing mapping in Ethiopia. Nevertheless, new transmission foci have been discovered in different parts of the country. The objective of this study was to assess the establishment of transmission and determine the prevalence of Schistosoma mansoni infection in school children from Sanja Town, northwest Ethiopia. METHODS: A cross-sectional parasitological survey involving 384 school children in two primary schools of Sanja Town was conducted between February and April 2013. Stool specimens were collected and microscopically examined using Kato-Katz and Sodium acetate-acetic acid-formalin (SAF) concentration methods. Malacological survey was also carried out to identify snail intermediate hosts and larval infection rate in the snail. The snails collected were checked for trematode infection by shedding. Observation was also made on water contact habits of the study population. RESULTS: The prevalence of Schistosoma mansoni infection using Kato-Katz method was high among male (79.5%) children in Sanja Primary school while it was high among female (75%) children in Ewket Amba Primary school. The prevalence of Schistosoma mansoni infection among Sanja Primary school children in the age groups 5–9 and 10–14 years were 84.6% and 75.2%, respectively while in Ewket Amba Primary school, the prevalence was 66% and 77.9% in the age groups 5–9 and 10–14 years respectively. The prevalence of schistosome infection in Biomphalaria pfeifferi was 16.9% and 0.027% during February and April, respectively. S. mansoni infection was successfully established in laboratory mice and adult worms were harvested after six weeks of laboratory maintenance. Observations made on water contact activities showed swimming, bathing and washing in the river and the stream as the high risk activities for Schistosoma mansoni infection. CONCLUSION: The study has shown establishment of transmission of schistosomiasis mansoni in Sanja Town. Therefore, appropriate integrated control measures need to be introduced to reduce morbidity in the population and also to control the transmission of schistosomiasis in the study area.