Human gastro-intestinal parasites in Bendel State, Nigeria.

Faecal samples from 862 male and female donors of nine age groups (1-90 years) in three geographical zones were screened by the examination of concentrates from formal other concentration technique. The overall percentage incidence of six parasites which were encountered were as follows: Entamoeba coli (19.7%), E. histolytica (3.9%), Giradia lamblia (1.4%), hookworm (29.4%), Ascaris lumbricoides (38.2%) and Trichuris trichiura (7.3%). However, the percentage incidence of parasites in the delta mangrove zone subject to heavy flooding and excess run-offs during the rainy season, were as follows: E. coli (44.7%), E. histolytica (0%), G. lamblia (37.5%), hookworm (44.9%), A. lumbricoides (51.0%) and T. trichiura (77.6%). Except for E. histolytica and G. lamblia, the percentage incidence in the delta zone were comparatively higher than values observed in the better drained middle rainforest and savanna zones. The age groups in the first two decades of life had 61.7% infection and this stabilised to a low level of 2.8% in the eighth and ninth decades. Males and higher protozoan and helminthic infections than females.