Current high prevalences of Strongyloides stercoralis and Opisthorchis viverrini infections in rural communities in northeast Thailand and associated risk factors

Two important helminths, Strongyloides stercoralis (an intestinal roundworm) and Opisthorchis viverrini (a liver fluke), are endemic in northeast Thailand. There have been national campaigns in place aimed at the control and eradication of soil-transmitted helminthiasis and opisthorchiasis in Thailand for several decades. However, these helminths still exist and raise concerns regarding public health. This study aimed to evaluate the current prevalence of S. stercoralis and O. viverrini infections in rural communities in northeast Thailand. The data from this study will be useful to improve strategies for future helminth prevention and control. A cross-sectional study was conducted from December 2016 to June 2017 in Mueang Khon Kaen district in Khon Kaen, Thailand. The participants were selected using a simple random sampling method. Demographic data were collected using a questionnaire. Stool samples were collected and processed using agar plate culture to determine the presence of S. stercoralis infection and an in-house formalin-ethyl acetate concentration technique to determine the presence of O. viverrini and other intestinal parasite infections (IPIs). In total, 602 persons were enrolled. However, only 526 were analyzed for S. stercoralis and 387 for O. viverrini risk factors. The overall prevalence of S. stercoralis infection was 23.0% (95% confidence interval [95%CI]: 19.4 to 26.6). The prevalence of O. viverrini infection and IPIs other than S. stercoralis was 20.4% (95%CI: 16.5 to 24.8). The prevalence of O. viverrini infection was 19.4% (95%CI: 15.6 to 23.7). Male sex was significantly associated with S. stercoralis infection [Adjusted Odds Ratio (aOR) 4.0; 95%CI: 2.5 to 6.2; P-value