The incidence of schistosomiasis in Bahir-Dar; Ethiopia

ABSTRACT

A study was made in Bahir-Dar; North-Western Ethiopia; for a period of twelve months; to determine the incidence of Schistosomiasis mansoni. All children aged 10 years and younger in Dil Chibo and Teyima Elementary Schools were stool-examined by the formol-ether concentration technique at the beginning of the study to select schistosomiasis mansoni negative children for a later incidence study. Accordingly; 139 children in Dil Chibo and 104 children in Teyima were found negative and used for an incidence study. In the incidence surveys; the stool specimens were examined by the Kato method. The overall annual incidence rates for Dil Chibo and Teyima school children were 194/1000 and 382/1000 respectively. The rates obtained at the second survey were higher than the rates obtained at the first survey; 164/1000 and 36/1000; respectively; for Dil Chibo and 292/1000 and 77/1000; respectively; for Teyima schools. Males had a higher schistosomiasis incidence than females (P0.01). The incidence also appeared to vary with age. The value of incidence as a measure of transmission is discussed