Authors

B Sripa¹;  ¹ WHO Collaborating Centre for Research and Control of Opisthorchiasis & Department of Tropical Medicine, Faculty of Medicine, Khon Kaen University, Thailand

Discussion

Human liver fluke infections caused by Opisthorchis viverrini and Clonorchis sinensis are major neglected foodborne trematodiases in Eastern and Southeast Asia, affecting over 30 million people. These infections are linked to various hepatobiliary diseases, including cholangiocarcinoma (CCA), a fatal bile duct cancer. Northeast Thailand, where O. viverrini is endemic, reports the highest incidence of CCA globally. Despite decades of liver fluke control programs in Thailand, the current infection status of O. viverrini remains high in certain endemic areas due to its complex life cycle involving multiple hosts/environments, posing challenges for conventional control methods. Consequently, a new control strategy for liver fluke infection using the One Health approach was introduced in the Lawa Lake area of Khon Kaen province, where the liver fluke has been highly endemic for over 15 years. As a result, the infection rate in over 20 surrounding villages has decreased to less than 5% from an estimated baseline of 60%, indicating significant progress. The local population has gained enhanced knowledge of liver fluke transmission and control. Notably, the prevalence of Cyprinid fish species, the intermediate hosts, has reduced to less than 0.1% from a maximum of 70% during the baseline survey, and liver fluke parasite cercariae have not been detected recently. This liver fluke control program, now named the "Lawa model", has gained national recognition and its principle is incorporated into the national agenda against liver fluke and CCA since 2016, with expansion to other regions of Thailand. Internationally, the "Lawa model" is celebrated as one of the two showcases with successful control programs for helminths, recognized by the WHO/NZD4 meeting in 2014. Furthermore, the One Health approach has been endorsed in the report of the Expert Consultation to Accelerate Control of Foodborne Trematode Infections, Taeniasis, and Cysticercosis in Seoul, Korea, by the WHO Western Pacific Region in 2017.