Pathological changes in the small intestine of neonatal pigs infected with a pig reovirus-like agent (rotavirus)

Abstract

Pathological changes in the alimentary tract of colostrum-deprived piglets infected with a pig rotavirus are described. Fourteen infected and 7 control piglets were killed at intervals over the period from 13 h post infection (p.i.) to 168 h p.i. Immunofluorescent staining showed that viral antigen was present in villous epithelial cells of the small intestine from 24 to 96 h p.i. Although fewer fluorescing cells were seen from 48 to 97 h p.i. on the villi, fluorescing cells were demonstrated in faeces up to 168 h p.i. Histopathological examination was carried out on 10 sites in the small intestine from the pylorus to the terminal ileum and villus length, crypt depth and mitotic index were measured in the duodenum, middle small intestine and terminal ileum. Pathological changes associated with the presence of viral antigen were confined to the small intestine. A reduction in villus length was first observed in the terminal ileum at 24 h p.i., and from 48 to 168 h p.i. marked stunting of villi in the middle small intestine and terminalileum occurred. Stunting and adhesion of the villi resulted in a flat, avillous mucosa, but the lesions were not uniform throughout the small intestine.