Strong association between high burden of soil-transmitted helminthiasis and household transmission among Malaysian Negritos, urging anthelmintic treatment beyond children

The Orang Asli (OA), Malaysia's indigenous minority, continue to experience ongoing soil-transmitted helminth (STH) infections despite efforts including the Resettlement Programme (RPS). This study explores STH epidemiology and associated risks of moderate-to-heavy infections among 259 indigenous Negritos across four states in Peninsular Malaysia. Stool samples, anthropometrics, haemoglobin levels (finger-prick) and sociodemographic and environmental-sanitation factors via pretested questionnaires were collected. Parasitological examinations (direct faecal smear, formol-ether concentration, and Kato-Katz techniques) were thoroughly performed. The study revealed a 63.3% overall STH prevalence, with Trichuris trichiura (57.9%) being the most common, followed by Ascaris lumbricoides (35.5%) and hookworm (8.9%). Moderate-to-heavy infections were observed in 39.3% for T. trichiura and 48.9% for A. lumbricoides, with mixed infections of these two species being the most prevalent (50.6%). The risk for moderate-to-heavy infection increased significantly if other household members were infected (P < 0.001). Adults and adolescents also showed high infection rates, with no significant differences with children's groups. These findings emphasize the need for anthelmintic treatment across all age groups and strategize local policies targeting older groups of the OA community to control ongoing transmission and reduce the STH burden and protect the future well-being of OA children, who deserve a healthier future.