Effectiveness of mebendazole and health education in control of pinworm infection among children living in low income settlements

Abstract

INTRODUCTION & OBJECTIVES: We aimed to evaluate the effectiveness of mebendazole (MBZ) mass treatment and health education in reducing reinfection with pinworm among children living in low income settlements (LIS). METHODS: A factorial cluster-randomized, controlled trial was conducted during January to May 2014, to compare the effectiveness of MBZ 100mg for positive cases versus mass treatment, and routine versus special health education. 1257 children aged 3-7 years, from 48 clusters of LIS in the Colombo Municipal Council area, were selected using cluster sampling. Perianal cellophane adhesive swabs (CAS) were examined for pinworm eggs. About 2-3 weeks after collection of the first sample (CAS1), depending on the intervention arm, eligible participants were given MBZ. Second sample (CAS2) was collected a week after administration of the first dose (MBZ1). Second dose (MBZ2) was given two weeks after MBZ1. Third sample (CAS3) was collected a week after MBZ2, and a fourth sample (CAS4) was collected 12 weeks after MBZ2. RESULTS: Sample collection rate was 94%, 80%, 75% and 73%, for CAS1, CAS2, CAS3 and CAS4 respectively. Overall egg positivity reduced from 42.5% to 10% following MBZ1, and to 6.8% following MBZ2, but increased to 29.3% at 12 weeks following MBZ2. In logistic regression, reinfection rate at 12 weeks after MBZ2 (i.e. those who were CAS3 negative but CAS4 positive) was associated with baseline pinworm egg positivity (OR=1.2) and BMI for age Z score (OR=0.96), but not with intervention arm. CONCLUSION: MBZ is effective in reducing pinworm egg positivity, but re-infection is common.