Newly identified endemic areas of Schistosomiasis mansoni in Tigray, northern Ethiopia.

A survey of Schistosomiasis mansoni and Snail hosts was conducted in 1992-93 in Tigray Region. Forty accessible communities were selected at random and a total of 4786 children from elementary and junior high schools were examined for Schistosomiasis mansoni infection. Schistosomiasis mansoni positive children were found in 32 (80%) communities with prevalences ranging from 1% to 66% and an overall prevalence of 18.4%. Human prevalences of 5% and above were observed in 25 communities of which 19 are newly identified endemic foci. Significantly more males than females were infected with Schistosomiasis mansoni (P < 0.05). The age group of 10-19 years was most affected (P < 0.001). Biomphalaria pfeifferi were collected in 20 (58.8%) habitats of the total of 34 water bodies surveyed covering 18 communities. Infected snails were recovered from 12 (60%) of the 18 communities surveyed and six of these were newly identified transmission foci. The distribution of intestinal schistosomiasis in Tigray and the possible factors contributing to its spread are discussed and possible tactics of control suggested.