PATTERNS OF INFECTION WITH SCHISTOSOMA-HAEMATOBIUM IN LAKESIDE RESETTLEMENT COMMUNITIES AT THE OYAN RESERVOIR IN OGUN STATE, SOUTH-WESTERN NIGERIA

Patterns of infection with Schistosoma haematobium were studied in 199 1 and 1992 in two, lakeside, resettlement communities at the newly est ablished Oyan Reservoir in Ogun State, Nigeria. Prevalence and intensi ty of S. haematobium infection and frequency of haematuria and protein uria all increased markedly from 1991 to 1992, indicating intensive tr ansmission. This was confirmed in an incidence study. In both years, i nfection patterns were highly age-dependent, with peaks in those aged 10-14 years. These patterns deviate from those seen during a survey ca rried out in the same communities in 1988, providing strong evidence t hat the infection had changed from an epidemic to an endemic stage. Al though sex, tribe, religion, occupation, and village of residence had little if any effect on infection patterns, the patterns in settled an d migrant groups differed considerably. The study provided a thorough elucidation of the complexity and instability of transmission of S. ha ematobium in a resettlement community characterized by social instabil ity and extensive population movements. Although haematuria was very c ommon, the subjects knew little about its cause.