돼지 유행성 설사증 (Porcine Epidemic Diarrhea) 감염 소장상피세포의 전자현미경 관찰

Ultrastructural Changes in Enterocyte infected with Porcine Epidemic Diarrhea Virus

The morphologic changes of small intestinal epithelium in pigs diagnosed as porcine epidemic diarrhea(PED} by virus isolation and immunohistochemistry were studied through light microscope and transmissible electron microscope. On semi-thin section, the histologic findings showed severe villous atrophy and fusion with hyperplasia of cuboidal epithelium in the villi, inflammatory cell infiltration in lamina propria, and increased mitotic figures in the crypt. The structural changes were mostly restricted to the cytoplasm of affected absorptive epithelium of villi. 3 types of epithelial changes were found; degenerated virus-affected cells, undifferentiated cuboidal cells, and normal columnar cells. On electron microscopy, round to spherical viral particles of 50∼l00nm in diameter were found within the dilated vesicles and endoplasmic reticulums of degenerated cells, which had decreased their cytoplasmic electron density due to dilated and missing organelles(e.g. mitochondria, ERs, etc.). Microvilli were shortened and sparse, leaving denuded terminal web of the villous epithelial cells. Fat globules were often found within slightly degenerated enterocytes. On the tip of villi, severely damaged cells were exfoliated and replaced by undifferentiated cuboidal cells We found distinct ultrastructural changes in the jejunal epithelium confirming PED virus infection is involved in malabsorptive diarrhea.