Behavioral and occupational factors associated with Schistosoma japonicum egg excretion in Napu Valley, an elimination-phase setting in Indonesia

Despite substantial reductions in schistosomiasis prevalence following repeated praziquantel administration, Schistosoma japonicum infection remains a concern in agricultural communities in Indonesia. This study aims to examine the relationship between behavioral and occupational factors and S. japonicum egg shedding as an indicator of parasite burden among farmers in the Napu Valley, Central Sulawesi, Indonesia. The study evaluates whether the use of personal protective equipment (PPE) and post-exposure hygiene practices are associated with lower egg counts in the context of this elimination phase. A community based cross sectional study was conducted among 132 farmers selected through proportional random sampling. Data on occupational exposure, water contact behavior, PPE use, and hygiene practices were collected using interviewer administered questionnaires. Stool samples were examined using the Kato Katz method, and infection intensity was quantified as eggs per gram of feces / egg density (EPG). Associations with egg counts were assessed using bivariate and multivariable linear regression analyses. Detectable S. japonicum egg excretion was identified in 30 participants (22.7%). Longer duration of farming work was associated with higher egg counts (ρ = 0.188; P = 0.031). Farmers who used boots and gloves had significantly lower egg counts (P = 0.006). In multivariable analysis, PPE use remained independently associated with lower egg counts (β = -0.452; 95% CI: -0.870 - -0.034; P = 0.034). Detectable S. japonicum egg excretion remains present among farmers in Napu Valley despite declining endemicity. Longer farming duration was associated with higher S. japonicum egg density, whereas consistent use of personal protective equipment was independently associated with lower parasite burden in this elimination phase setting.