Hookworm infection in Kweneng District, Botswana, A prevalence survey and a controlled treatment trial.

Stool specimens from a sample of schoolchildren at six schools in Kweneng District were examined for hookworm infection, using the brine flotation method. Necator americanus was the only hookworm identified. The western part of the District forms part of the Kalahari Desert, and in four villages here 90%, 88%, 88% and 86% of the children were infected. In two villages in the eastern non-desert part, only 13% and 9% were infected. Most infections were light. There was no significant correlation between severity of infection and anaemia. In one school (228 pupils; 86% infected with hookworm), half the children were treated with tetrachloroethylene (0.1 ml/kg, maximum 5 ml) and the other half with placebo. Two weeks after treatment the prevalence of infection were 28% and 75% respectively (p less than 0.001), and five months after treatment 51% and 69% (p less than 0.05). Measured over the five-month period there were no significant changes in haemoglobin and nutritional status (weight/height). Based on the results of the survey, a hookworm mass treatment programme was not recommended.