Contribution of wastewater irrigated vegetables to the prevalence of soil-transmitted helminth infection among female farmers in Addis Ababa, Ethiopia

Abstract

Abstract Background Untreated or inadequately treated wastewater carrying human feces can host helminth eggs and larvae, contaminating the soil and plants that are irrigated with it. In Addis Ababa, farmers use untreated wastewater to grow vegetables; however, there are little data currently available published on vegetables' contribution to the prevalence of helminth among female farmers along the Akaki River, in Addis Ababa, Ethiopia. Methods A cross-sectional study was conducted in Addis Ababa City in February 2022. A stratified random sampling method was used to sample farming households. The sample size for each district was determined by a proportional allocation to the total number of households in the area. Two hundred and fifty-two composite vegetable samples and 101 farmers’ stool samples were collected and analyzed for helminth prevalence. Data on socio-demographics were collected by trained data collators using a structured questionnaire. Kato-Katz concentration was used to detect STH from a stool sample. Stata version 14.0 was used to process the data. Poisson regression was used to identify the association between STH prevalence in the vegetable and the farm's stool. Results Helminths were found in 67.5% of vegetables sampled and 20.8% of female farmers' stools. Ascaris lumbricoides eggs (vegetable 48.4% and stool 9.9%) were identified in all analyzed samples. Hookworm eggs (vegetable 13.1% and stool 8.9%) and Trichuris trichiura eggs (vegetable 5.9% and stool 2%) were also isolated. The total number of helminth eggs present in wastewater-irrigated vegetables and female farmers’ stool had a positive association (p < 0.05) with a regression coefficient of 1.92 (95% CI = 1.56–2.28). Conclusions The study found a significant prevalence of helminth infections, particularly Ascaris lumbricoides, in stool and vegetable samples irrigated with wastewater. A clear association was found between vegetable production and a higher prevalence of helminth infections among female farmers. Therefore, it is important to ensure that farmers are educated in the importance of food washing and sanitation/hygiene practices when using wastewater irrigation for vegetable crops. Graphical Abstract