Schistosoma mansoni and soil-transmitted helminth infections among schoolchildren living along the shore of Lake Hawassa, southern Ethiopia.

Abstract

Background: Schistosoma mansoni and soil-transmitted helminth (STH) infections are major public health problems in areas with poor sanitation and limited access to water. In Ethiopia, there is limited data available for monitoring the efficacy of interventions aimed at reducing helminth infections. Therefore, we assessed the prevalence of S. mansoni and STH infections, as well as factors associated with this prevalence, among schoolchildren and compared the findings with those of earlier studies. We also evaluated the diagnostic agreement between two parasitological methods.

Methods: A cross-sectional study involving 363 schoolchildren from three rural primary schools located along the shore of Lake Hawassa, Sidama Regional State, southern Ethiopia, was conducted in October and November 2023. The schoolchildren were selected using a systematic random sampling technique. Socio-demographic data were collected using pre-structured questionnaires. A single stool sample was collected from each study participant and processed using direct wet mount (DM) microscopy and the formol-ether concentration technique (FECT) to detect helminth ova.

Results: The overall prevalence of helminths was 59.8%, with 36.6% of participating children having a single infection and 23.1% having multiple infections. Schistosoma mansoni and STHs were present in 33.9% and 38.8% of children, respectively. The STHs included Ascaris lumbricoides (28.9% of children), Trichuris trichiura (10.7%), hookworms (5.2%) and Strongyloides stercoralis (2.8%). Diagnostic agreement between the DM microscopy method and FECT was substantial [kappa (κ) = 0.710] for the detection of Hymenolepis nana and almost perfect (κ = 0.827) for the dection of A. lumbricoides, but only fair for the detection of other detected helminths. Children at Finchawa primary school had a lower prevalence of S. mansoni infection [adjusted odds ratio (AOR) 0.31; 95% confidence interval (CI) 0.13-0.76] than those at St Paul's Tullo Catholic primary school. STH infections were more common among children who sometimes (vs. always) washed their hands before meals (AOR 1.89; 95% CI 1.01-3.54) and those who regularly played with soil (AOR 2.56; 95% CI 1.47-4.46).

Conclusions: This study showed a reduction in STH infections from a high prevalence in 2015 to a moderate prevalence at the present time, despite a similar moderate prevalence of S. mansoni infection. Thus, it is crucial to intensify deworming interventions to reduce the burden of helminths in the study area. Additionally, there is a need to enhance the capacity of clinical laboratories to perform FECT in Ethiopian clinical settings where DM is often employed to diagnose helminths.