Community-wide deworming strategies to reduce high hookworm burden in endemic communities: Results from a cluster randomized trial in southern India

ObjectivesTargeted deworming of high-risk groups (usually school-based programs), although effective in controlling morbidity, may not be sufficient to reduce hookworm burden in endemic communities due to the persistence of infection in the adult population. The effectiveness of community-wide mass drug administration (MDA) strategies were evaluated in a hookworm-endemic tribal community in southern India. MethodsIn this open-label, cluster-randomized community-intervention trial, 45 villages comprising of 2770 households were randomly assigned (1:1:1) to receive community-wide MDA with albendazole at modified intervals: 1) single-cycle, 2) two-cycles (one month apart) and 3) four-cycles (two cycles one month apart, followed by another two after six months). The primary outcome was the prevalence of hookworm infection, and the co-primary outcome was the mean intensity of infection at 12 months post-MDA, assessed through a cross- sectional coprological survey. Secondary outcomes included prevalence and intensity of infection after each MDA cycle and at 3-, 6-, 9- and 24-months post-intervention. Analysis was by intention-to-treat. This trial is registered with the Clinical Trials Registry - India (CTRI/2013/05/003676). ResultsThe prevalence (95% confidence interval) of hookworm infection at baseline was 14.8% (11.1-19.5%), 18.5% (15.4-22.0%) and 22.4% (17.4-28.2%) in the single-, two-, and four-cycle arms, respectively, which reduced to 5% (2.9-8.6%), 4% (1.8-8.4%) and 1.2% (0.3- 4.0%) at 12 months post-intervention. At 12 months post-intervention, both prevalence (OR=0.41; P=0.016) and intensity (IRR=0.29, P<0.001) of infection were significantly lower in the four-cycle arm as compared to the single-cycle arm, but the difference was not statistically significant at 24 months. No statistically-significant difference in prevalence or intensity of infection was observed between single- and two-cycle arms at any time-point. ConclusionsMultiple cycles of community-wide MDA may help reduce the burden of hookworm in endemic communities, but improvement in water, sanitation, and hygiene practices are needed for long-term sustainability. Author SummaryEvidence suggests that community-wide deworming might work better than targeted school- based deworming in reducing hookworm infection rates in endemic populations. We evaluated the effectiveness of modified community-wide deworming strategies in reducing hookworm burden in an endemic community in southern India. Forty-five tribal villages were randomized in a 1:1:1 ratio to receive either a single-cycle, two-cycle (two rounds one month apart), or four-cycle (two rounds one month apart and then another two after six months) of community- wide deworming. The prevalence and intensity of infection were measured at baseline and 3, 6, 9 12 and 24 months after treatment through cross-sectional surveys. The post-treatment prevalence of hookworm infection reduced considerably in all the three treatment arms. Compared to the single-cycle arm, prevalence and intensity of hookworm infection were significantly lower in the four-cycle arm at 3, 6 and 12 months after deworming; prevalence or intensity of infection did not differ significantly between the single- and the two-cycle arms at any time point. The findings of this study suggest that multiple rounds of community-wide deworming may help reduce hookworm burden in endemic communities, but long-term sustainability will require improvement in water, sanitation, and hygiene practices.