Pathogenesis of Rotaviral Enteritis in Gnotobiotic Pigs: A Microscopic Study

Open Access
Publisher Website
Google Scholar
Abstract
SUMMARY: The pathogenesis of rotavirus (rv) infection was studied in gnotobiotic pigs orally inoculated with a field isolate of porcine rotavirus. Virus-intestinal cell interactions were examined by fluorescent antibody technique, light microscopy, and scanning and transmission electron microscopy. Clinical signs of diarrhea were observed in inoculated pigs at postinoculation hours (pih) 12 through 96. Examination of negative-stained fecal preparations revealed large numbers of coreless rotaviral particles in fecal material collected at pih 24 to 72, whereas nearly 100% of the virus particles were complete in fecal samples collected at pih 96. Specific fluorescence was observed in the cytoplasm of a few villous absorptive cells in the duodenum and upper portion of the jejunum (uj) at pih 12 with the most intense fluorescence at pih 24 to 96 in the absorptive cells of villi in the uj through the midportion of the small intestine. Virus replication resulted in desquamation of villous absorptive cells in the lower portion of the jejunum (lj) through the upper portion of the ileum (ui) beginning at pih 24. In the uj through the ui, the loss of villous absorptive cells resulted in a progressively shortened villi beginning at pih 24 and was most severe in inoculated pigs killed at pih 72 to 84. Crypt hyperplasia was observed in the uj through the ui at pih 60 to 96, resulting in replacement of villous absorptive cells, as evidenced by an increase in cuboidal villous epithelial cells present at pih 72 to 96 and an apparent increase in the length of villi at pih 96. Segments of the small intestine examined by scanning electron microscopy revealed villous fusion, rounded absorptive cells, villous atrophy, and exposure of the lamina propria especially in the lj through the ui. Thin sections of the small intestine examined by transmission electron microscopy revealed rv particles in the absorptive cells of the midportion of the small intestine and duodenum through the ui at pih 12 and 24, respectively. Cytoplasmic lysis of absorptive epithelial cells was evident at pih 36, and viral particles were observed in the lumen near microvilli. Rotavirus-induced changes in the small intestine of gnotobiotic pigs were characteristic of those described for natural rv infection.

This publication has 0 references indexed in Scilit: