Pathology of Neonatal Calf Diarrhea Induced by a Reo-Like Virus

Abstract

Gross, immunofluorescent, and light microscopic findings in seven gnotobiotic calves inoculated orally with a Reo-like neonatal calf diarrhea virus were compared to findings in three control gnotobiotic calves. Neonatal calf diarrhea virus infected primarily the villous epithelium of the small intestine. Calves examined within 1.5 h after onset of diarrhea had tall columnar immunofluorescent villous epithelial cells in the middle and lower small intestine. Calves examined 2–4.5 h after onset of diarrhea had cuboidal to squamous villous epithelial cells and an increase in reticulum-like cells in the villous lamina propria of the middle and lower small intestine. Viral tilers were 106 and 108 in colonic contents from two calves inoculated with cell-culture-adapted virus and necropsied, respectively, 2 and 6 h after onset of diarrhea.

Gnotobiotic Piglets Experimentally Infected with Neonatal Calf Diarrhoea Reovirus-Like Agent (Rotavirus)

“…In mice, however, stunting of the villi was not seen [1, 161, but epithelial cells at the tips of villi sloughed, and those remaining were vacuolated and had eosinophilic cytoplasmic inclusions. Cytoplasmic inclusions were not reported in calves [12] and were not seen in our piglets. These differences in the severity of the lesions between species may be related to the host, to the infective dose, to the strain of virus, or to the stage of the disease at which samples were taken.…”

“…Lesions seen with the light microscope in the small intestines of calves were similar to lesions in our study. The stunting of villi in our piglets was more severe than that reported in other studies on calves [12,25]. Villi of piglets infected with a rotavirus strain derived from a field case of enteritis in pigs were as severely stunted as the villi in our study in which a calf virus was used [unpublished observations].…”

“…These differences in the severity of the lesions between species may be related to the host, to the infective dose, to the strain of virus, or to the stage of the disease at which samples were taken. The most severe stunting in our piglets was at 68 h after inoculation, 50 h after the onset of diarrhoea, whereas the calves in another study were killed between 19 and 31 h after inoculation, less than 6 h after the onset of diarrhoea [12,181. The mice were examined 24 h after the onset of diarrhoea.…”

“…Studies of the pathology of animals infected with rotavirus have been confined to calves [12,15,181 and mice [ I , 21. This paper describes the pathological changes in gnotobiotic piglets experimentally infected with a strain of rotavirus originally isolated from a calf.…”

Serial Studies of Virus Multiplication and Intestinal Damage in Gnotobiotic Piglets Infected with Rotavirus

“…The pathogenesis of rotavirus infection has been described in calves (Mebus et al, 1971), piglets Pearson and McNulty, 1977) and lambs (Snodgrass et al, 1977), but these studies did not correlate the severity of the intestinal lesions with virus production over the course of the infection. There is a possible criticism of the present attempt to study the virus content of particular sections of gut, namely that peristalsis caused mixing of virus along the gut.…”