The liver and biliary tract from 10 autopsies in Udorn, Thailand, where 90% of the population is infected with the liver fluke Opisthorchis viverrini, were examined by cholangiography, dissection, and microscopy. Liver flukes were found in 7 cases and evidence of previous infection was noted in 2. In addition to the presence of flukes, focal dilatations, constructions, and retention cysts were the principal findings both in the cholangiograms and on dissection. Periportal fibrosis, inflammation, and biliary epithelial hyperplasia were found on microscopical examination. Because of the bland nature of the inflammatory reaction and the long asymptomatic period, we conclude that the changes observed are not a reaction to an antigen or toxin of the fluke, but that mechanical obstruction of the intrahepatic bile ducts by flukes raises the pressure within the biliary tree, inducing slow but progressive inflammatory and fibrotic responses.
Present address: Department of Pathology, University of West Virginia Medical Center, Morgantown, West Virginia 26506.
Alternate address: SEATO Medical Project, U. S. Component, APO San Francisco, California 96346.