Date of Award

1982

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

A canine rotavirus isolate caused clinical disease, small intestinal lesions, serum antibody response, and shedding of rotavirus in the feces in newborn gnotobiotic dogs. The results of this study demonstrated this rotavirus was a pathogen in neonatal gnotobiotic dogs. The pathogenesis of the intestinal lesions was similar to the pathogenesis of rotaviral enteritis in other species. In three consecutive experiments, twenty puppies were derived by caesarean section and transferred to sterile isolators. Gnotobiotic puppies were inoculated orally with a rotavirus isolated from a neonatal puppy with fatal diarrhea. Fecal samples from the puppies were examined for virus particles by negative contrast electron microscopy. Infected and control puppies were killed at 12, 18, 24, 48, 72, 96, 132, and 154 hours post-inoculation (PI). Tissue samples were collected for fluorescent antibody, light, scanning electron, and transmission electron microscopy. Serum samples were examined for rotaviral antibody by a fluorescent antibody test. The rotavirus isolate did infect the small intestine of the inoculated puppies. Diarrhea was observed in the inoculated puppies at 20 to 24 hours PI, persisting throughout the experiment. Rotavirus particles were observed in fecal samples of inoculated puppies 12 through 154 hours PI. Rotavirus group-specific immunofluroescence was seen in intestinal villus epithelial cells at 12 hours PI in the duodenum, jejunum, and ileum. Fluorescnece persisted in the jejunum and ileum through 154 hours PI. Morphological lesions in the small intestines were confined to the jejunum and ileum. Light and scanning electron microscopy revealed swelling and necrosis of villus epithelial cells with loss of epithelium. Slight to moderate villus atrophy was observed and the villi were covered by flattened to cuboidal epithelial cells. Rotavirus particles, rotaviral precursor material, and necrotic villus epithelial cells were seen early in the infection by transmission electron microscopy. In the later stages of infection, villus epithelial cells were similar, ultrastructurally, to crypt epithelial cells. Serum rotavirus antibody was detected in infected puppies killed at 96, 132, and 154 hours PI. This rotavirus isolate caused moderate enteritis in gnotobiotic puppies and could serve as a model for pathogenesis studies of rotavirus infection in other species.

Pages

133

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