Scanning electron microscope studies of the mucosa of rats infected with Hymenolepis diminuta (Cestoda).

The intestinal morphology of rats given one, 10 or 100 cysticercoids of hymenolepis diminuta was examined by scanning electron microscopy. The presence of this tapeworm causes extensive villous atrophy and fusion. The most extreme changes in mucosal architecture were observed adjacent to the mature proglottides of the worm and in these areas the villi were reduced either to flattened plate-like structures or to low irregularly shaped undulations. The presence of one large H. diminuta resulted in more severe pathological damage than caused by several smaller worms. Colonization of the upper region of the ileum by long filamentous bacteria was also observed in rats infected with H. diminuta.