Human schistosomiasis in Ngamiland, Botswana.

To reassess the schistosomiasis problem in Ngamiland and especially in Maun area 552 primary school children and 213 adult labourers were examined with urinalysis and rectal snip. Of the pupils 80.3% were found positive for S. mansoni and 1.4% for S. haematobium; of the labourers 35.7% were infected with S. mansoni and 0.5% with S. haematobium. There was no difference between the sexes; prevalence decreased by age. In Seronga village 102 pupils were examined; 69.6% were positive for S. mansoni. The decrease in prevalence in the higher age groups may be explained by recent introduction of the agent in the area.