Schistosoma haematobium infection patterns in the Rahad Irrigation Scheme, Sudan.

Patterns of infection of urinary schistosomiasis (Schistosoma haematobium) were studied in 4 highly endemic village areas in the Rahad Irrigation Scheme, Sudan. The prevalence of S. haematobium infection in the total study population of 4725 individuals was 30%, and the age-prevalence and age-intensity figures increased rapidly to reach their maxima in the younger age groups. The overall prevalence of infection among males (31.7%) was slightly higher than among females (28.7%), and the two sexes differed in their age-specific prevalence patterns. The pattern of intensity of infection in males and females was rather similar. Marked differences in prevalence and intensity of S. haematobium infection were recorded between the four village areas, and the infection level in camp inhabitants exceeded markedly that in village inhabitants. Specific problems related to low school attendance rates, limited use of treatment opportunities provided at health centers and less than optimal efficacy of the focal snail control approach taken may be kept responsible for the fact that the control programme implemented in the Scheme has not achieved transmission control.