Pathological and immunohistochemical study of the liver and hepatic lymph nodes in goats infected with one or more doses of Fasciola hepatica

Lesions produced by Fasciola hepatica in the liver, gall-bladder and hepati c lymph nodes (HLNs) of four groups of five goats are described; in additio n, the distribution of CD3(+) T lymphocytes and IgG-lambda light chain-bear ing cells was analysed in the hepatic lesions and HLNs. One group of goats received a single oral dose of metacercariae, but the other four groups rec eived four or five doses at different intervals over a period of II weeks. Animals that survived were killed 53-55 weeks after the first infective dos e. Goats were more susceptible to multiple doses than to a single dose, eve n when the total number of metacercariae was the same. This greater suscept ibility was manifested by the occurrence of deaths and the severity of hepa tic lesions. CD3(+) lymphocytes were sparse in the infiltrate surrounding t he acute migratory tracts, suggesting inhibition of the local cell-mediated immune response. Goats with numerous hepatic calcareous granulomas showed the most severe hepatic damage, including marked cirrhosis, with a striking infiltrate of CD3(+) T lymphocytes and lambda IgG(+) plasma cells, replaci ng extensive areas of hepatic parenchyma, in which hypertrophy of the smoot h endoplasmic reticulum of hepatocytes was evident. These findings were obs erved mainly in the goats given more than one infective dose. (C) 1999 W.B. Saunders Company Limited.