Liver fluke infection caused by Opisthorchis viverrini is a major public health problem in Thailand and
the Lao People’s Democratic Republic (Lao PDR; Laos). Currently, more than 600 million people are at
risk of infection with these fish-borne trematodes and/or their close relatives. Opisthorchiasis has been
studied extensively in Thailand, where about 8 million people are infected with the liver fluke. Here
we review the pathogenesis, control and re-emergence of O. viverrini infection, in particular in Thailand
and, to a lesser extent in Lao PDR given the contiguous geographical range of O. viverrini through these
two regions. We also review the association of O. viverrini infection and cholangiocarcinoma, bile duct
cancer, and highlight new findings on pathogenesis of liver fluke-induced cholangiocarcinogenesis. Last,
we comment on national control strategies in Thailand for the control of O. viverrini infection aimed at
reduction in the prevalence of O. viverrini-associated liver cancer in the longer term.