Soil contamination with soil-transmitted helminths and associated hygiene and environmental sanitation conditions among model and non-model villages in Jimma Zone, southwest ethiopia: a comparative community-based cross-sectional study

Soil contamination with Soil-transmitted helminths (STHs) eggs and infective larvae constitutes the most important risk factor for human parasitic infections. STHs remain a major public health concern in low-resource settings, particularly in areas with poor hygiene and inadequate environmental sanitation. This study assessed soil contamination rate with soil-transmitted helminths and associated hygiene and environmental sanitation conditions among model and non-model villages under the Health Extension Program in Jimma Zone, southwest Ethiopia. A comparative cross-sectional study was conducted among model and non-model villages. A total of 240 soil samples were collected from five sampling sites within six randomly selected model and six non-model rural villages during both dry and rainy seasons. The soil samples were examined using the Zinc sulfate flotation technique. A total of 120 households, consisting of 60 model and 60 non-model households, were selected for the household-level assessment. Household hygiene and environmental sanitation data were systematically collected using a structured questionnaire. Data were analyzed using SPSS version 22. Descriptive statistics were used to summarize the data, and chi-square tests were applied to compare model and non-model villages. Statistical significance was set at P < 0.05. The overall soil contamination rate with soil-transmitted helminths (STHs) was 12.5%, with contamination higher during the rainy season than the dry season. Strongyloides stercoralis larvae were the most frequently detected parasites, followed by hookworm, Trichuris trichiura , and Ascaris lumbricoides ova. In the multivariable analysis, soil samples from non-model villages had significantly higher odds of contamination than those from model villages (AOR = 3.30; 95% CI: 1.18–9.24; p = 0.023). Contamination was also significantly higher during the rainy season than the dry season (AOR = 3.34; 95% CI: 1.19–9.37; p = 0.022). At the household level, non-model households were more likely to have contaminated soil (AOR = 6.54; 95% CI: 4.36–9.82; p < 0.001). Households without latrines (AOR = 3.33; 95% CI: 1.08–11.91; p = 0.045), those with irregular shoe wearing (AOR = 2.09; 95% CI: 1.12–4.53; p = 0.034), and those practicing open-field waste disposal (AOR = 2.03; 95% CI: 1.33–2.82; p = 0.029) had significantly higher odds of soil contamination. The findings suggest that soil contamination with different species of soil-transmitted helminths (STHs) was significantly higher in non-model household villages than in model household villages and during the rainy season. At the household level, lack of latrine ownership, irregular shoe wearing, and open-field waste disposal were significant predictors of contamination. Strengthening the model household approach, sanitation, safe waste disposal, and personal hygiene practices, particularly during the rainy season, may help reduce environmental contamination and STH transmission.