Soil-Transmitted Helminth Infections among Plantation Sector Schoolchildren in Sri Lanka: Prevalence after Ten Years of Preventive Chemotherapy

摘要

Mass de-worming of pre-school and school-age children was introduced in Sri Lanka's plantation sector in 1994 after a survey showed that >90% of children and women of reproductive age were infected with intestinal worms. The present study was carried out to assess the status of infection four years after mass de-worming was stopped in 2005 due to lack of funds. Approximately 20 children from each of 114 schools in five districts were examined. Data regarding the school, the child's family and household sanitation were recorded. Faecal samples from 1890 children were examined for worm eggs. In 4/5 districts, >20% were found infected with one or more intestinal worm. Overall, 29.0% of children were infected and 11.6% of these had moderate–heavy worm burdens. The commonest infection was roundworm, followed by whipworm. Hookworm was not detected in two districts. Statistical analysis identified low altitude, maternal under-education and poor household sanitation as risk factors for infection. The results indicate that when initial infection rates are very high, in the absence of marked improvements in sanitation and health education, even 10 years of biannual mass de-worming may not be enough to prevent resurgence of infection after cessation of mass de-worming.