Soil-transmitted helminth infections after mass drug administration for lymphatic filariasis in rural southern India.

ABSTRACT

OBJECTIVES: Targeted deworming is the current strategy for control of morbidity associated with soil-transmitted helminths (STH) among at-risk populations preschool-aged children, school-aged children and women of childbearing age. We report the prevalence and intensity of STH in a district after lymphatic filariasis (LF) mass drug administration (MDA) in southern India where albendazole was co-administered from 2001. METHODS: Children aged 2 to 15 years and adults (defined as ≥15 years) in a rural administrative block of Tamil Nadu were recruited using a probability proportional to size method. Stool samples were screened and eggs per gram (EPG) determined by Kato-Katz method. Multilevel logistic regression (MLR) and multilevel negative binomial regression (MNBR) analyses were used to identify factors associated with infection and intensity, respectively. RESULTS: Of 862 participants who provided samples, 60 (7.0%; 95% confidence interval (CI) 5.3-8.7) were positive for STH with a predominance of hookworm infections (n = 57, 6.6%; 95% CI 5.0-8.3). Increasing age (odds ratio (OR) 1.09; 95% CI 1.04-1.15) and regular usage of the toilet (OR 0.32; 95% CI 0.12-0.88) were independently associated with hookworm infection and age was significantly associated with increasing intensity of hookworm infection (infection intensity ratio (IIR) 1.28; 95% CI 1.19-1.37). A brief review of STH prevalence in endemic settings before and after the stoppage of LF MDA indicated that, in most settings, a substantial reduction in STH prevalence is seen. CONCLUSION: Community-wide MDA in all age groups in these post-LF MDA districts with low prevalence and light intensity infections could result in transmission interruption of STH.