Patterns and risk factors for helminthiasis in rural children aged under 2 in Bangladesh

Abstract

Objectives. To obtain knowledge on the burden of infestation with soil-transmitted helminths (STHs) in rural children from birth to age 2 years. Methods. Household visits to enrolled children were made twice a week for 2 years, and stool samples were collected once a month. Stools were also collected during diarrhoeal episodes, and when STHs were identified, a single dose of pyrantel pamoate was administered to patients with diarrhoea. All stool samples were examined using the formalin-ether sedimentation technique. Results. About 70% of the children had had STH infestation by 2 years, and approximately 80% of these had STH ova identified on more than one occasion. The mean age at first acquisition was 14 months (standard deviation (SD) 4 months, range 1 - 24 months). Microscopic examination revealed ova of Ascaris lumbricoides (9%), Trichuris trichiura (0.6%), hookworm (0.06%) and mixed infestation (0.4%). In 41 of the 178 children with STH infestation, its first identification was associated with episodes of diarrhoea. Following pyrantel pamoate deworming, 66% of subjects were re-infested after a mean interval of 90 days (SD 79 days). Risk behaviours such as disposal of child faeces and defaecation by adult family members in open spaces and use of common source surface water for washing clothes and utensils were practised by 62%, 83% and 50% of the cohort families, respectively. Bivariate analysis shows that disposal of child faeces in a closed space resulted in a 35% reduction in helminth infestation (odds ratio (OR) 0.65, 95% confidence interval (CI) 0.49 - 0.87), use of tube well water in a 48% reduction (OR 0.52, 95% CI 0.29 - 0.93, p<0.02) and breastfeeding in a 16% reduction (OR 0.84, 95% CI 0.64 - 1.10, p<0.2). Mutivariable analysis adjusted with risk variables shows a 5.06 times higher odds of recognising STH infestation during an episode of diarrhoea (OR 5.06, 95% CI 3.8 - 6.69, p<0.0001). Conclusion. Awareness building programmes and periodic deworming are crucial to prevent acquisition of, re-infestation with and spread of STH.