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D R Snodgrass

Publications and source records attributed to D R Snodgrass.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1977

Serological relationships between rotaviruses from different species as studied by complement fixation and neutralization.

Human, piglet, mouse, foal, lamb, calf and rabbit rotaviruses all infected, but could not readily be subcultured in LLC MK2 cells. Cells infected with mouse and calf rotaviruses reacted by indirect immunofluorescence (FA) with convalescent serum from children, piglets, mice, foals, lambs, calves or rabbits, taken after rotavirus infection. Human, calf, piglet, mouse and foal rotaviruses reacted with human, calf, mouse, foal and lamb convalescent serum by complement fixation (CF). It was not possible to distinguish between different rotaviruses by CF or FA. Neutralization tests, however, detected species-specific rotavirus antigens. Any virus was neutralized by a much higher dilution of homologous species convalescent serum than by any heterologous serum. With the exception of the mouse virus there was very little cross reaction. However, in sera with a very high neutralizing titre for the homologous virus the titre was proportionately raised against heterologous virus. It is, therefore, now possible to type to species an unknown rotavirus by a neutralization test in LLC MK2 cells using convalescent serum from each species.

Animals↗
PubMed1977

Human rotavirus in lambs: infection and passive protection.

A human stool filtrate containing rotavirus which was administered orally to gnotobiotic lambs caused diarrhea, virus excretion, development of antibodies to rotavirus, and pathological changes in the villi of the small intestine. Thus, lambs may serve as experimental animals for the study of human rotavirus infections. This model system was used to study passive protection. Human immunoglobulin G (IgG) containing antibody to rotavirus was fed to lambs 24 to 78 h after birth, and the lambs were infected with lamb-passaged human rotavirus when 30 h old. The lambs treated with IgG did not develop diarrhea, and virus excretion was delayed in onset and shortened in duration. It may be possible to make similar use of IgG to protect children at risk in a rotavirus outbreak. The treatment did not prevent the lambs developing antibody to rotavirus.

Administration, Oral↗
PubMed1976

Isolation of Reovirus type 2 from respiratory tract of sheep.

A virus isolated from a nasal swab taken from a healthy lamb was identified as a reovirus on the basis of morphology and physicochemical characteristics. This virus agglutinated human 0 erythrocytes and was shown by haemagglutination tests to be a type 2 reovirus. Serological evidence indicated infection of other healthy lambs in the same group.

Animals↗
PubMed1976

Rotavirus infection in lambs: studies on passive protection.

Gnotobiotic lambs were protected against rotavirus infection by the presence in the gut at the time of infection of colostrum or serum containing antibodies to rotavirus. This protection was observed even when passively-acquired antibody was not present in the serum of the infected lamb. Infection under these conditions may have conferred immunity to subsequent challenge.

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↗
PubMed1976

Chemotherapy of experimental bovine petechial fever.

A dithiosemicarbazone was compared with two tetracycline formulations in the treatment of bovine petechial fever (BPF) in experimentally infected sheep, and was then used to treat the disease in experimental cattle. The dithiosemicarbazone was found to be more efficacious than either of the other two drugs in treating ovine BPF, and also to be effective against BPF in cattle.

Animals↗
PubMed1975

The role of wild ruminants in the epidemiology of bovine petechial fever.

After experimental inoculation of Cytoecetes ondiri, the agent of bovine petechial fever (BPF), multiplication occurred in impala, bushbuck, Thomson's gazelles and wildebeest, as shown by infectivity studies and clinical findings. Similar attempts to infect one eland failed. As a sequel to this, blood and spleen samples were collected from four species of wild ruminants in an area where BPTF was endemic. Isolations of C. ondiri were made from three of five bushbuck, but not from any other species.

Animals↗