Opisthorchis viverrini infection remains a significant public health concern in Southeast Asia, particularly in rural communities of Northeast Thailand, where persistent environmental and behavioral factors sustain transmission. A quasi-experimental study aimed to identify environmental and behavioral risk factors for infection and to evaluate the effectiveness of a community-based intervention program. The intervention program study was conducted over 10 months and comprised three phases: baseline survey‚ health education intervention program implementation‚ and follow-up evaluation. The results were analyzed for the prevalence of parasitic infections, and multivariable logistic regression was performed to identify associated factors. The majority of study participants were female (67.94%)‚ aged 55 to 64 years (48.09%)‚ and farmers (89.31%). Parasitic infections‚ especially O. viverrini‚ substantially decreased during the follow-up period‚ and independent risk factors predicting infection included lower education‚ previous infection‚ raw fish consumption‚ and pesticide use‚ according to multivariable logistic regression analysis. This intervention considerably improved knowledge; mean knowledge score increased by 6.29 points (p < 0.001). Analysis of fecal sludge after treatment with the sand-drying system identified S. stercoralis larvae (20 eggs/L) and Taenia spp. eggs (12.4 eggs/g). These findings indicated that, despite treatment, integrated behavioral and environmental interventions can be effective in interrupting parasite transmission in rural endemic settings.

Lead (Pb) is a persistent environmental contaminant and a major public health concern. This cross-sectional study investigated self-reported health symptoms and estimated dietary Pb exposure from aquatic animal consumption among residents living around Nong Han Lake, Thailand. Sociodemographic characteristics, dietary behaviors, and health symptoms were collected using a structured questionnaire. Pb concentrations were measured in three commonly consumed aquatic species, and species-specific estimated dietary Pb intake (EDI) was calculated from Pb concentrations and reported consumption patterns. Multivariable logistic regression identified factors associated with symptom reporting. Pb concentrations in all aquatic species were below the permissible limit (0.3 mg/kg wet weight). Median EDI was 0.1004 µg/kg bw/day (IQR: 0.0645–0.1785). Musculoskeletal pain (79.73%) and joint and muscle pain (71.62%) were the most commonly reported symptoms. This study found that female sex (aOR = 2.62; 95% CI: 1.099–6.249; p = 0.030), a lack of lead hazard training (aOR = 3.39; 95% CI: 1.373–8.418; p = 0.008), consumption of more than 300 g of aquatic animals per meal (aOR = 2.47; 95% CI: 1.230–4.960; p = 0.011), and long-term consumption exceeding 30 years (aOR = 2.16; 95% CI: 1.065–4.398; p = 0.033) were each independently associated with symptom reporting. Estimated dietary Pb intake (EDI) was not significantly associated with symptoms after multivariable adjustment (aOR = 1.30; 95% CI: 0.657–2.578; p = 0.450). These findings suggest that consuming large portions of aquatic animals, consuming aquatic animals over prolonged periods, and having limited awareness of lead-related hazards are potential pathways for dietary Pb exposure in this lake-dependent community.