Prevalence and intensity of <I>Schistosomiasis mansoni</I> in irrigation and non-irrigation areas of central Kenya

Abstract

To compare the extent of intestinal schistosomiasis among school children attending school in an irrigation and non-irrigation area of Central Kenya. A cross sectional study. Three separate parasitological surveys involving four primary schools in Mwea irrigation scheme, Kirinyaga District and two from a non-irrigation area in Machakos District. One thousand two hundred and twenty two children aged between five and nineteen years were examined for Schistostoma mansoni infection by Kato thick smear technique. High prevelances ranging from 73% to 94% were noted among children in all the participating schools. Overall 41% of the infected children had heavy infection (>400 eggs per gram), 27% had moderate infection (101-400 epg) and 32% had light infection (10-100epg). When data from the two areas were analysed seperately, peak eggs output were found in 5-9 year olds among children in Kirinyaga while this situation shifted to the 10-14 year olds in Machakos children. In Kirinyaga District, boys in the 10-14 years age group had a significantly higher output than girls (P<0.01), but this situation was reversed in the older children (P<0.05). Girls in Machakos District had consistently but non-significantly higher output than boys. Intestinal schistomiasis is more prevalent and with a higher intensity in the irrigated than in non-irrigated areas. There were also pronounced age and gender related differences in the pattern of infection between the two study areas.