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Biomedical subjects

E W Gray

Publications and source records attributed to E W Gray.

At least 37 records · Page 2Linked to original sources
PubMed1981

Purification and characterization of ovine astrovirus.

Astrovirus, purified in aggregated form from epithelial cells of the small intestinal villi of infected gnotobiotic lambs, was shown to have a single-stranded RNA genome with an S value of 34 and poly(A) tract. Only two major capsid polypeptides were detected with similar mol. wt. of approx. 3.3 x 10(4).

Animals↗
PubMed1981

Diarrhea in lambs experimentally infected with Cryptosporidium isolated from calves.

Two to 5 days after oral inoculation with Cryptosporidium obtained from infected calves, 7 newborn specific-pathogen-free lambs became depressed and anorectic and developed diarrhea. Four moribund lambs were killed within 3 days after onset of illness, and the 3 other lambs died after protracted intermittent diarrhea and reduced milk intake, which lasted up to 14 days. The small and large intestines were heavily infected with Cryptosporidium, with the terminal portion of the ileum being the most severely affected. Histologic examination revealed villous atrophy, with considerable fusion and epithelial cross-bridging between villi. Lambs infected at 5 to 20 days of age had less severe clinical signs of disease, with intermittent diarrhea, reduced milk intake, and growth retardation. Lambs infected at 30 days of age became infected with the organism, but did not develop clinical signs of disease or growth retardation.

Animals↗
PubMed1980

Virus infections in cattle and sheep in Scotland 1975-1978.

Over the four-year period 1975-78 attempts were made to identify virus in samples from 1231 outbreaks of disease in cattle, and 682 outbreaks of disease in sheep. A virus identification was possible in 26 per cent of these disease outbreaks. The nature and significance of these virus infections is discussed.

Animals↗
PubMed1980

Ultrastructure of the small intestine in astrovirus-infected lambs.

The ultrastructure of the small intestine of gnotobiotic lambs infected with lamb astrovirus was studied. The virus was observed from 14 to 28 h p.i. in mature columnar epithelial cells covering the apical two-thirds of villi. Crystalline arrays of virus particles with a centre to centre distance of approx. 29 nm were seen in the cytoplasm and virus particles were also observed in apical pits and tubules and in lysosomes. Macrophages containing virus particles in lysosome-like organelles were seen in the lamina propria. Virus particles were released by desquamated cells disintegrating in the gut lumen. Cuboidal cells lining villi appeared from 38 to 70 h p.i., and by 120 h p.i. the villi appeared normal.

Animals↗
PubMed1979

Pathogenesis of diarrhoea caused by astrovirus infections in lambs.

Experimental infection of 2-day-old gnotobiotic lambs with lamb astrovirus produced mild diarrhoea after an incubation period of about 48 hours. No other clinical symptoms developed. Infection was studied by immunofluorescent and histological examination of tissues from the lambs. Astroviruses infected only mature villus epithelial cells and subepithelial macrophages in the small intestine, where they produced partial villus atrophy. Infected enterocytes were replaced with cuboidal cells from the crypts, and the lesion gradually healed by 5 days after infection. No serological relationship was detected by immunofluorescence between lamb astrovirus antigen in gut sections and antisera to either calf or human astrovirus.

Animals↗
PubMed1977

Rotavirus infection in lambs: pathogenesis and pathology.

Experimental lamb rotavirus infections were studied by immunofluorescence, histopathology and electron microscopy of tissues from infected gnotobiotic lambs killed at intervals from the incubation period to recovery. The rotavirus was demonstrated by immunofluorescence only in epithelial cells of villi in the small and large intestine, and virus antigen was most abundant during the incubation period. An increased enterocyte turnover rate was suggested by the rapid movement of virus-infected cells to the villus tip, and this increase may be one of the basic pathogenic mechanisms of rotavirus infection. Principal histopathological changes were shortening of villi and sloughing of epithelial cells. These were greatest in the middle and posterior small intestine at the onset of diarrhoea, but regeneration occurred within a few hours. Virus morphology in tissues was similar to that reported in other species, and virus presence correlated well with histopathological change.

Animals↗
PubMed1977

Detection and transmission of 30 nm virus particles (astroviruses) in faeces of lambs with diarrhoea.

An outbreak of diarrhoea in lambs was investigated, and electron microscopic examination revealed small round virus-like particles in the faeces from eight of seventeen lambs. A bacteria-free filtrate of faeces from one lamb was given orally to a gnotobiotic lamb, which subsequently excreted virus in faeces. Intestinal contents were collected from this lamb and a filtrate given orally to two further gnotobiotic lambs, which subsequently developed diarrhoea and excreted virus in faeces. The mean diameter of the virus particles was 29.7 nm, and 12 per cent of them showed their surface structure arranged in the form of a six-pointed or five-pointed star. They were similar to those particles previously observed in human infant faeces which were referred to as "astroviruses". The passage through gnotobiotic lambs with development of diarrhoea showed that these particles were animal viruses which were probably pathogenic for lambs.

Animals↗
PubMed1976

A rotavirus in lambs with diarrhoea.

A reovirus-like agent was identified from an outbreak of enteritis in young lambs. From its morphology and immunological relationship with calf rotavirus, it was concluded that it was a rotavirus which infects lambs.

Animals↗