Exploring factors associated with Trichuris trichiura infection in school children in a high-transmission setting in Kenya

Kenya has implemented a National School-based Deworming Programme (NSBDP) which has led to substantial decline in prevalence of soil-transmitted helminths (STH), although some pockets of infections still remain. To effectively design a STH control programme that leads to significant reductions of T. trichiura there is a need to understand the drivers of persistent infection despite ongoing treatment programme. This study was conducted between July and September 2019 at the south coast of Kenya, using a two-stage sampling design. First, a school-based cross-sectional survey was conducted among 2,265 randomly school children from selected schools in areas known to be endemic for T. trichiura. Following this, we conducted a nested case control study whereby all children positive for T. trichiura (142) were matched to 148 negative controls on the basis of age and village. A household survey was then conducted with all household members of both cases and controls. In addition, a subsample of 116 children found to be infected with T. trichiura were followed to assess the efficacy of albendazole at day 21 post-treatment. Predictors of presence of T. trichiura were investigated through multilevel logistic regression considering clustering of infection. Overall, 34.4 % of the children were infected with at least one STH species, T.trichiura was the most common (28.3%), 89.1% of those with T. trichiura had light intensity infections. Prevalence of T.trichiura was significantly higher among male children, and was positively associated with younger age, number of people infected with T.trichiura in a household . The parasitological cure rate (CR) and Egg Reduction Rate (ERR) of T.trichiura were 35% and 51%.Other STH identified were hookworm (9.6%) and A. lumbricoides (5.7%). Trichuris trichiura remains a significant public health challenge in the study area with albendazole treatment efficacy against the parasite remining lower than the WHO recommended thresholds. Due to the observed focal transmission of T. trichiura in the current area, control efforts tailored to local conditions and targeting lower implementation units should be utilized to achieve optimal results on transmission.