High infection risk of intestinal helminths despite WASH interventions: A cross-sectional study in Khammouane province, Lao PDR

BACKGROUND: Despite the widespread implementation of water, sanitation and hygiene (WASH) program over the last two decades, Lao People's Democratic Republic (Lao PDR) remains highly endemic for intestinal helminth infections. We assessed the intestinal helminth infections burden and the link with WASH levels in an area with WASH interventions. METHOD: A cross-sectional study was conducted across 81 villages in Khammouane province, Lao PDR, where WASH interventions were implemented. Villages and 30 participants (aged 18-87 years) per village were randomly selected. Demographics, individual and household data, including WASH-related factors were collected. Stool samples were examined for intestinal helminth infections using formalin-ethyl acetate concentration technique (FECT). Logistic regression analysis was performed to identify risks associated with intestinal helminth infections. RESULTS: A total of 1530 participants were included. Multi-helminth species infection was very common, e.g., 30.1% had a double infection. Opisthorchis viverrini was most prevalent (56.9%), followed by hookworm (54.7%), minute intestinal flukes (22.7%), and Trichostrongylus spp. (10.7%). Overall, 56.1% and 44.4% had access to safely management water services and sanitation facilities, respectively, and 17.7% practiced open defecation. Improved WASH levels were not associated with reduced intestinal helminth infections. District of residence, age, gender and raw food consumption predicted helminth infections. E.g., O. viverrini infection was associated with residency in Mahaxai district (Mahaxai, aOR = 14.0; 95% CI = 9.5-20.6; p < 0.001 and Bulapha, aOR = 3.0; 95% CI = 2.0-4.4; p < 0.001). CONCLUSION: Our findings indicate a high intestinal helminth infections burden in this province, with several risk factors such as location, age, gender and consumption of raw food predicting helminth infection. Improved WASH levels are not associated with reduces prevalence of intestinal helminth infection in this cross-sectional study.