The prevalence, intensity and morbid1ty of schistosomiasis among the school children from Rusinga Island, Lake Victoria in Kenya

Abstract

A cross-sectional descriptive study of schistosomiasis was carried out on the school children residing on Rusinga Island of Lake Victoria in Kenya. Between February and December, 1986 a total of 2620 pupils (79.5%) out of 3294 registered in the Island's schools were examined. 247 pupils (9.4%) were found to be infected with schistosome eggs; (88.3% with schistosoma mansoni, 11.7% with S. haematobium and 0.2% with both). Of those infected with S. haematobium 24(82.8%) had haematuria (confirmed by reagent strips) and out of these 24, 21(91.3%) had more than 50 eggs per 10ml of their urine specimens. Of those with S. mansoni infection, 76(73,1%) had bloody stools (confirmed by occult blood test) out of whom 70(97.2%) had more than 100 eggs per gram of their faecal specimens. Only three pupils out of the 218 with S. mansoni had hepatomegaly but all.three had more than 200 eggs per gram of their faecal specimens. There was no relationship between splenomegaly and S. mansoni, infection as only two (1.9%) of those infected had splenomegaly whereas 49(3.7%) had splenomegaly but no S. mansoni infection. Intensity of schistosomiasis was found to have no apparent effect on the academic performance of the infected pupils nor did it influence their weight for age. Potential intermediate snail hosts for S. mansoni identified from the Island included Biomphalaria pfeifferi, B. choanomphala and E. sudanica while those for S. haematobium were Bulinus (Physopsis) africanus, B (Ph) nasatus, and B. (Ph) globosus. Apart from schistosomiasis 172 pupils (6.6%) had Ascaris_1umbricoides, 136 (5.2%) had Trichuris trichiura, 67(2.6%) had hookworm, 44(1.7%) had Entamoeba histolytica and 21 pupils (0.8%) had Giardialamblia.