Abstract:
According to the Kenya National School-Based Deworming program launched in 2012 and
implemented for the first 5 years (2012-2017), the prevalence of soil-transmitted helminths (STH)
and schistosomiasis substantially reduced over the mentioned period among the surveyed schools.
However, this reduction is heterogeneous. In this study, we aimed to determine the factors
associated with the 5-year school-level infection prevalence and relative reduction (RR) in
prevalence in Kenya following the implementation of the program. Multiple variables related to
treatment, water, sanitation, and hygiene (WASH) and environmental factors were assembled and
included in mixed-effects linear regression models to identify key determinants of the school
location STH and schistosomiasis prevalence and RR. Reduced prevalence of Ascaris
lumbricoides was associated with low (< 1%) baseline prevalence, seven rounds of treatment, high
(50-75%) self-reported coverage of household handwashing facility equipped with water and soap,
high (20-25°C) land surface temperature, and community population density of 5-10 people per
100 m2. Reduced hookworm prevalence was associated with low (< 1%) baseline prevalence and
the presence of a school feeding program. Reduced Trichuris trichiura prevalence was associated
with low (< 1%) baseline prevalence. Reduced Schistosoma mansoni prevalence was associated
with low (< 1%) baseline prevalence, three treatment rounds, and high (> 75%) reported coverage
of a household improved water source. Reduced Schistosoma haematobium was associated with
high aridity index. Analysis indicated that a combination of factors, including the number of
treatment rounds, multiple related program interventions, community- and school-level WASH,
and several environmental factors had a major influence on the school-level infection transmission
and reduction.