To demonstrate the feasibility of interrupting STH transmission through MDA-based approaches in settings where LF programs have progressed to post-MDA surveillance
In order to test the feasibility of interrupting the transmission of STH, the DeWorm3 Project conducted a series of community, cluster-randomized trials in Benin, India, and Malawi.
Lymphatic filariasis (LF) programs delivered at least five years of community-wide mass drug administration (MDA) with albendazole in DeWorm3 sites and have successfully transitioned to post-MDA surveillance status in each area. This epidemiological setting provides an opportunity to leverage the success of the LF programs to understand how further intensified drug pressure influences the feasibility of interrupting the transmission of STH.
DeWorm3 study sites have 80,000-100,000 inhabitants per site, with 40 clusters of 1,650-4,000 inhabitants each. Clusters randomized to the intervention arm of the trial received twice yearly community-wide MDA targeting eligible individuals of all ages. Clusters randomized to the control arm of the trial received the country’s standard of care treatment targeting pre-school and school-age children. Treatment was delivered for three years, and will be followed by two years of surveillance during which no MDA will take place in either trial arm in order to monitor for infection recrudescence.
Exhaustive population censuses and school-facility surveys were conducted at study baseline and updated annually to identify all individuals living in the study sites and key STH risk factors present at individual, household, and school levels.
STH prevalence is determined via cross-sectional surveys at study baseline, 6 months following the final round of MDA, and 24 months following the final round of MDA (i.e. post surveillance). Longitudinal surveys were also conducted to ascertain infection and reinfection patterns within the same cohort of individuals over time. A random selection of stool samples were examined via duplicate Kato-Katz and all samples will be examined for STH genetic material via quantitative PCR through the UW DeWorm3 grant, given the low prevalence expected after multiple years of intensified MDA.
For more information on the DeWorm3 trial design, the DeWorm3 trial protocol can be found here.