Impact on prevalence of intestinal helminth infection in school children administered with seven annual rounds of diethyl carbamazine (DEC) with albendazole

BACKGROUND & OBJECTIVES: One third of the world's population is infected with one or more of the most common soil-transmitted helminths (STH). Albendazole (ALB) is being administered with diethyl carbamazine (DEC) in filariasis endemic areas to eliminate lymphatic filariasis (LF) and helminth infections. In this study, the cumulative impact of seven annual rounds of mass drug administrations (MDA) of DEC and ALB on STH infection in school children in selected villages in southern India was determined. METHODS: During 2001-2010, seven MDAs were implemented by the Tamil Nadu State Health Department, India. LF and STH infections were monitored in school children from 18 villages of the two treatment arms (viz, DEC alone and DEC+ALB). Kato-Katz cellophane quantitative thick smear technique was employed to estimate STH infections at three weeks, six months and one year post MDA. RESULTS: Prior to treatment, an overall STH prevalence was 60 per cent. After each MDA, infection markedly reduced at three weeks post-treatment in both the arms. The prevalence increased at six months period, which was maintained up to one year. After seven rounds of MDA, the infection reduced from 60.44 to 12.48 per cent in DEC+ALB arm; while the reduction was negligible in DEC alone arm (58.77 to 52.70%). INTERPRETATION & CONCLUSIONS: Seven rounds of MDA with DEC+ALB reduced the infection load significantly, and further sustained low level of infection for 10 years. However, complete parasite elimination could not be achieved. To curtail STH infection in the community, MDA should be regularized and environmental sanitation measures need to be improved by effective community-based campaigns.