Cross-sectional patterns of hepatobiliary abnormalities and possible precursor conditions of cholangiocarcinoma associated with Opisthorchis viverrini infection in humans

The liver fluke, Opisthorchis viverrini, is both highly prevalent and closely associated with cholangio-carcinoma in northeast Thailand. This study measured associations between intensity of liver fluke infection and nonmalignant hepatobiliary disease diagnosed by ultrasonography among 1, 807 largely asymptomatic adult residents drawn from endemic communities. Abnormalities significantly associated with intensity of infection included gallbladder enlargerment in all dimensions, presence of sludge, irregular gallbladder wall, liver enlargement, and enhanced portal vein radicle echoes. While gallbladder enlargement was not sex-specific, the prevalence odds of the other abnormalities were 2-3 times higher among males compared with females. Those recently treated with the anthelmintic praziquantel had higher odds of these abnormalities compared with others with the same infection status who were untreated. The low prevalence of gallstones suggests that this impairment of gallbladder structure and function does not frequently stimulate gallstone formation. However, gallbladder disturbances, together with chronic inflammation and fibrosis of the bile ducts, which are visualized as enhanced portal vein radicle echoes, may contribute to the strikingly enhanced susceptibility to cholangiocarcinoma among people, especially males, with heavy liver fluke infection.