Helminth prevalence among adults in rural Kenya: a stool survey for soil-transmitted helminths and schistosomiasis in Nyanza province.

BACKGROUND Soil-transmitted helminth (STH) prevalence in children is high in rural southwestern Kenya, but adult prevalence data are scarce. A 2010 study of a village in Nyanza province found a pediatric STH prevalence of 44% using a direct stool-smear method. Adult STH prevalence and associated predictors was measured in the same village. METHODS Adults (≥18 years) presenting at the out-patient department of the small hospital or community outreach events completed a short questionnaire and provided stool samples. Light microscopy for ova and larvae was conducted using a stool concentration technique to improve sensitivity. Multivariable regression models were used to identify predictors of STH prevalence. RESULTS Among 344 adults, STH prevalence was 15.7% (54/344). Hookworm was most common (13.1%; 45/344), followed by Ascaris lumbricoides (6.1%; 21/344) and Trichuris trichiura (0.6%; 2/344). Twelve participants (3.5%; 12/344) had multiple STHs and three (0.9%; 3/344) had Schistosoma mansoni. Female sex, older age and lower education level were significant STH predictors. CONCLUSIONS Adult STH prevalence was lower than previous studies of children from the same village. Adults with the identified risk factors had a prevalence of ≥20%, which may warrant periodic, targeted deworming of adults with these risk factors given the low cost and low toxicity of anthelmintic drugs.