The epidemiology and control of hookworm infection in the Burma Valley area of Zimbabwe.

An integrated hookworm control programme, involving mass chemotherapy and improvements in public health, was conducted in the Burma Valley and Vumba areas of Zimbabwe between 1985 and 1990. Three sequential annual mass chemotherapy programmes were implemented. Infection status was monitored annually throughout. Initial observations indicated asymptotic age prevalence and intensity profiles, with peak infection levels in adults. Mass chemotherapy was shown to have immediate and medium term benefits for community health. Reinfection was slow to develop, and average intensity had not returned to pre-intervention levels 39 months after the cessation of chemotherapy. The results support the existence of age-dependency in reinfection. Despite a marked increase in the number of sanitation units, no relationship was found between latrine availability and reinfection intensity on individual farms. This result is consistent with observations that the effect of sanitation is slow to develop, and indicates that repeated anthelmintic intervention should be maintained until sanitation has an impact on transmission.