Effectiveness of seasonal community-basedmass-expulsion chemotherapy in the control of human hookworm infections in endemic communities

Abstract

The effect of seasonal application of mass-expulsion chemotherapy (MEC) on theepidemiological status of hookworm infection was investigated on a “target” population in a hookworm endemic area. The application of MEC reduced the egg counts of infected individuals by values ranging from 80 to 96%. The percentage reduction in egg count did not depend on the season of application of MEC. The infection rate (conversion) and the rate of loss of infection (reversion) were however affected by the season of application of MEC. Conversion rates of 18%, 17% and 10% were recorded for the early rain, heavy rain and dry seasons respectively. Reversion rates of 82%, 83% and 90% were recorded for the respective seasons. Post-MEC longitudinal studies showed a prevalence of 15% which showed a post-MEC decline of 45%. On the basis of these results, continuous application of MEC irrespective of season is recommended as a control for endemic hookworm infections.