Histopathology of Small Intestines of Rats and Mice Experimentally Infected with Pygidiopsis summa

Abstract

A histopathological study was performed on the intestine of rats and mice experimentally infected with Pygidiopsis summa. Total 16 rats and 12 mice were infected orally each with 1,000 metacercariae collected from the mullets. After 3 days to 5 weeks their small intestines were studied. While controls showed only a slight degree of non-specific inflammation in the villous stroma, those infected with P. summa revealed diffuse and remarkable mucosal changes during the early stage up to 2-3 weeks of infection. The mucosal pathology was chiefly villous atrophy (thickening, blunting of tips and fusion) with severe stromal inflammation, accompanied by crypt hyperplasia. No invasion of worms into the submucosa was recognized. Later than 3 weeks, however, the diseased mucosa began to restore their normal features. At 4-5 weeks mucosal layer became normal, except for slight stromal inflammation and/or crypt hyperplasia.