Follow-up of Ascaris lumbricoides and Trichuris trichiura infections in children living in a community treated with ivermectin at 3-monthly intervals.

Ivermectin treatment was administered every 3 months over a 1-year period (April 1993-April 1994) to the whole eligible population of a village in South Cameroon where both Ascaris lumbricoides and Trichuris trichiura were hyper-endemic. A parasitological stool examination was performed before each treatment. Thirty children, aged 5-15 years, were not only found egg-positive for A. lumbricoides and/or T. trichiura before the first treatment but were also each treated and examined in each treatment round. Among these children, the intensity of infection with A. lumbricoides decreased significantly following the first treatment but thereafter remained steady. In contrast, the repeated ivermectin treatments had no significant impact on the intensity of the T. trichiura infections or on the prevalence of infection with T. trichiura or A. lumbricoides among the 30 children.