Opisthorchis viverrini

Opisthorchiasis is a disease caused by liver fluke genus Opisthorchis, such as O. felineus and O. viverrini. This particular type of human liver fluke is notably prevalent in Thailand. The opisthorchiasis induced by O. viverrini remains a critical health concern widely distributed across continental Southeast Asia (SEA) countries, especially Thailand, Myanmar, Lao PDR, Cambodia, and Vietnam. Approximately 10 million people in endemic areas are estimated to be infected with this fish-borne trematode (Sithithaworn & Haswell-Elkins, 2003). Infection occurs through the consumption of undercooked freshwater fish containing O. viverrini metacercariae. Infected individuals excrete O. viverrini eggs-contained feces into the natural reservoir. These eggs are subsequently consumed by 1st intermediate host snails of the genus Bithynia. Within Bithynia snails, the eggs develop into cercariae, a free-swimming stage that encysts in muscle, skin, and fin of the 2nd intermediate host, freshwater fish (Sripa et al., 2021). Not only humans but also other fish-eating mammals can contract the infection by consuming uncooked or raw fish harboring the metacercariae (Sripa et al., 2007). As a consequence of the infection, individuals face the risk of developing hepatobiliary diseases, including cholangitis, cholecystitis, advanced periductal fibrosis (APF), and the potentially fatal bile duct cancer, cholangiocarcinoma (CCA). Additionally, It is also hypothesized that cats and dogs serve as reservoir hosts for O. viverrini (Petney et al., 2018).