Neonatal Calf Diarrhea. Electron Microscopy of Intestines Infected with a Reovirus-Like Agent

Abstract

Abstract. Neonatal calf diarrhea induced by a reovirus-like agent was studied by electron microscopy. Gnotobiotic calves were inoculated with virulent and cell-cultureadapted isolates of viruses, and similar results were obtained with both isolates. The virus infected mature villous epithelial cells of the small intestine and replicated predominantly within cisternae of the endoplasmic reticulum. Macrophages within small intestinal villi also contained viral particles. Shedding of virus into the feces apparently resulted from desquaniation of infected epithelial cells. Replacement epithelium did not contain the reovirus-like agent, was of cuboidal or squamous type, and ultrastructurally resembled immature epithelium normally found in the crypts. Escherichia coli was nonpathogenic when inoculated alone and did not adhere to the epithelium when inoculated with the virus. The reovirus-like agent was a primary pathogen since it caused diarrhea and lesions when inoculated alone or with E. coli.Diarrhea of neonatal calves has been a serious and persistent problem of the dairy industry for many years. This disease has become a major problem on ranches with cow-calf operations. Apparently an increased frequency of neonatal calf diarrhea in beef-type calves has been caused by calving during a relatively short period of time in the late winter and early spring when inclement weather causes stress. Cows and their offspring have been concentrated into small areas during the calving season, and transmission of infectious diseases to susceptible calves has been favored.A virus designated initially as neonatal calf diarrhea virus was isolated in 1968 and reported as an etiologic agent in field cases of neonatal calf diarrhea [9]. The disease was reproduced experimentally in specific pathogen-free and gnotobiotic calves inoculated with bacteria-free filtrates obtained from infected calves. Fecal material purified by ultracentrifugation and examined by

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells

“…The demonstration of rotavirus replication in phagocytic cells agrees with reports by different investigators who described the presence of rotavirus particles in subepithelial phagocytic cells, suggesting that this may be a mechanism of virus interaction with the immune system (5)(6)(7)13,14). The observation of rotavirus replication in phagocytic cells but the absence of viral replication in MA-104 cells inoculated with the lysate of these phagocytic cells suggests the production of defective viral particles.…”

Bovine coronavirus peplomer glycoproteins: detailed antigenic analyses of S1, S2 and HE

“…Bovine coronavirus (BCV) is an enteric virus which multiplies in the differentiated enterocytes of the small intestine and colon, causing acute enteritis in newborn calves (Stair et aL, 1972;Babiuk et al, 1985) and chronic shedding (Crouch et al, 1985) or diarrhoea (Takahashi et aL, 1980) in adult cows. BCV particles consist of large single-stranded positive RNA (30 kb) associated with a basic phosphonucleoprotein (N, Mr 52K) forming a helical ribonucleoprotein protected by a viral envelope containing three glycoproteins, M, S and HE (Laporte & Bobulesco, 1981;King & Brian, 1982;.…”

Antigenic and Biological Relationships between Human Coronavirus OC43 and Neonatal Calf Diarrhoea Coronavirus

“…Coronaviruses have been implicated in the aetiology of human gastroenteritis (Caul & Clarke, 1975;Caul et al, 1975;Caul & Egglestone, 1977;Lennartz et al, 1978). Neonatal calf diarrhoea coronavirus (NCDCV) is an important cause of diarrhoea in newborn calves (Stair et al, 1972;Mebus et al, 1973), but antiviral activity to NCDCV has been found in human sera, suggesting a possible role of a related coronavirus in gastroenteritis of humans (Sharpee & Mebus, 1975;Kaye et al, 1975). In addition, a close antigenic relationship between OC43 and NCDCV (both adapted to growth in suckling mouse brain) has been detected using complement-fixation, haemagglutination-inhibition (HI) and neutralization tests (Kaye et al, 1975).…”