School enrolment in Zanzibar linked to children's age and helminth infections

School health programmes have been identified as a cost-effective strategy to reduce morbidity due to soil-transmitted helminths in the school-age population, but the low rate of school enrolment in developing countries is a major factor limiting their success. OBJECTIVE: The present study was conducted to identify reasons for non-enrolment and to evaluate differences in the occurrence of helminth infection between enrolled and non-enrolled children in Zanzibar, United Republic of Tanzania. METHOD: A questionnaire was submitted to 520 households to obtain information about enrolment and other socio-economic indicators. In addition, one school-age child was randomly selected in each household and investigated for soil-transmitted helminth infection. RESULTS: Overall, 71% of school-age children were enrolled. Enrolment increased with age. Only 41% of children under 9 years of age were enrolled compared to 91% in children older than 12 years. Enrolment is delayed because of an insufficient number of schools. Among non-enrolled school-age children, the proportion of heavy intensity infections was twice that of enrolled school-age children. CONCLUSIONS: Most of the non-enrolled school-age children live together with enrolled siblings in the same household, thereby representing an important opportunity for effective outreach activities. The effectiveness of the school-based helminth control programme in reducing the intensity of infection was confirmed. The significant gains achieved by enrolled school-age children in this study must be viewed as an attainable goal for the important numbers of non-enrolled school-age children in endemic areas. Decision-makers must ensure that outreach activities are included in helminth control programmes targeted to school-age children.