Debouck, P., Pensaert, M. and Coussement, W., 1981. The pathogenesis of an enteric infection in pigs, experimentally induced by the coronavirus-like agent, CV 777.Vet. Microbiol., 6: 157--165.Sixteen 2--3-days-old caesarean-derived, colostrum-deprived piglets were each dosed oro-nasally with 2 ml of a bacteria-free filtrate containing 104 pig-infectious-doses of CV 777. The piglets were killed at intervals of 12 to 120 h after infection. The coronavirus-like agent caused a local infection of the intestinal tract which resulted in villous atrophy, malabsorption and diarrhea. The pathogenesis of this infection was similar to that of transmissible gastroenteritis (TGE), a known coronaviral infection of pigs. However, there were some differences. By immunofluorescent staining, CV 777 antigens were not only detected in the epithelial cells covering the small intestinal villi, but also in the cells of the colonic surface epithelium. Occasional fluorescence was also seen in the small intestinal crypt epithelium, but the regenerative capacity of the crypts was not affected. The progress of intestinal epithelial cell infection by CV 777 was much slower than that in TGE, resulting in a longer incubation period and in less drastic epithelial cell destruction. The infection of regenerating cells occurred to a much higher degree during the late stage of a CV 777 infection than has been observed in TGE.0378-1135/81/0000--0000/$02.50

A possible antigenic relationship between the porcine enteropathogenic coronavirus-like agent (CVLA) and 6 known coronaviruses was examined by immunoelectron microscopy (IEM) and by immunofluorescence (IF). CVLA did not show cross reactivity with infectious bronchitis virus, transmissible gastroenteritis virus (TGEV), canine coronavirus (CCV) hemagglutinating encephalomyelitis virus (HEV), neonatal calf diarrhea coronavirus (NCDCV) or feline infectious peritonitis virus (FIPV). Antigenic relationship was detected by IEM between TGEV and CCV, NCDCV and HEV and by IF between TGEV and CCV, TGEV and FIPV, HEV and NCDCV.

Abstract. Sixteen cesarean-derived colostrum-deprived piglets were infected oronasally with CV777 coronavirus on the second or third day of life. Two uninfected piglets were controls. They were killed at 96 and 120 hours after birth. After an incubation period of 22 to 36 hours, all principals showed severe diarrhea. The principals were killed between 12 and 120 hours after infection.Exfoliation of enterocytes was seen first in the piglet killed 24 hours after infection (two hours after the diarrhea began). From that time on, shortening and fusion of villi was present in all small intestinal parts. Affected cells showed vacuolation. The histochemical study showed that infected piglets had decreased activity of all four enzymes studied. The light microscope showed no lesions in the absorptive colonic epithelium.The significance of the lesions in relation to intestinal dysfunction is discussed, and lesions are compared to those of transmissible gastroenteritis and porcine rotavirus infection.

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family (14). WOODE et al. (27) and THOULESS et al. (24) have shown that antigenic relationships exist between rotaviruses from different animal species.The porcine rotavirus has been associated with acute diarrhea in unweaned or weaned pigs by WOODE et al. (26) in England, by MCNULTY et al. (12) in Northern Ireland, by LECCE et al. (10) in the United States of America, by RODGER et al. (20) in Australia, by PROZESKY and THEODORIDIS (19) in South Africa and by DEBOUCK and PENSAERT (4) in Belgium.The present report describes the results of experimental infections with 3 Belgian field isolates of the porcine rotavirus. Some attempts to cultivate the virus in cell cultures are also reported. Material and Methods Source of the virus isolatesThe first isolate, designated RV 277, was obtained from pooled watery feces of three piglets which showed acute diarrhea four days after they had been removed from the sow at the age of two days for other experimental purposes. All three pigs died.The second isolate, designated RV 377, originated from the intestinal contents of a five-day old piglet obtained from a conventional farm on which a mild outbreak of diarrhea occurred in five successive litters. The sows were asymptomatic. The piglets with diarrhea were not depressed and retained good appetite. No pig died. U. S.