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Biomedical subjects

K W Angus

Publications and source records attributed to K W Angus.

At least 91 records · Page 5Linked to original sources
PubMed1979

Chronic infection with Trichostrongylus vitrinus in sheep. Some effects on food utilisation, skeletal growth and certain serum constituents.

The effect on food utilisation and skeletal growth of daily infection for 90 days with 2500 Trichostrongylus vitrinus larvae was investigated. Controls were killed initially or fed ad libitum. Food intake, digestibility of dry matter and nitrogen and content of body fat, protein, water and minerals were determined, and selected bones examined chemically and histologically. Serum constituents were determined weekly. Digestibility of food dry matter and nitrogen were reduced during weeks 3 and 5 after initial infection but subsequently recovered. Deposition of fat, protein, calcium and phosphorus in the body was reduced by 36, 58, 67 and 78 per cent respectively. Gross efficiency of utilisation of metabolisable energy was reduced by 36 per cent. Bone changes were associated with a reduction in osteoblastic activity. Hypoalbuminaemia, hyperglobulinaemia and hypophosphataemia were present in infected sheep. There were no significant changes in serum calcium or urea concentrations. It is concluded that the effects of continuous intakes of T vitrinus and T colubriformis larvae on host metabolism are essentially the same.

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

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

Subclinical trichostrongylosis in growing lambs produced by continuous larval dosing. The effect on performance and certain plasma constituents.

Three groups of eight-four-month-old worm-free lambs were used to investigate the effect of Trichostrongylus colubriformis infection on growth rate, food intake, and concentration of plasma constituents. Groups ALC and ALI were fed ad libitum, the latter being dosed daily with 2500 infective larvae for 14 weeks. Lambs in group PF were paired to individuals in group ALI and offered the same quantity of food as the infected pair consumed. Hypophosphataemia and hypoalbuminaemia developed in ALI at week 3 and hyperglobulinaemia was present from week 6. There was no significant difference in plasma calcium, protein, urea or glucose concentration between the three groups at any stage. No clinical signs of parasitism were seen in seven of eight ALI lambs and egg counts were generally less than 2000 epg. Worm burdens of 1500-82,900 were found at slaughter. Group weight gain was only 50 per cent of PF lambs which received the same digestible energy intake. Group ALI consumed 15-5 kg dry matter per kg gain in bodyweight compared with 8-6 kg/kg and 9-8 kg/kg for ALC and PF respectively. The infections resulted in extensive villous atrophy and flattening of the intestinal mucosa. Bone growth was arrested and osteoporosis present in five group ALI lambs. The possible use of plasma constituents, particularly phosphorus, as aids for the diagnosis of the early stages of trichostrongylosis in the field is assessed.

Animals↗
PubMed1976

The specificity and sensitivity of the fluorescent antibody test for Mycobacterium johnei infection in abattoir and culled cattle.

In a series of 100 cattle in which there was no bacteriological or histopathological evidence of Mycobacterium johnei infection there were four positive reactions to the fluorescent antibody (FA) test with M johnei antigen and 20 to the complement fixation (CF) test. In a second series of 118 culled adult cattle M johnei infection was found in 26. The FA test was positive in 16 and the CF in 12 of those infected cattle. In 92 cattle with no evidence of M johnei infection the FA test was positive in seven and the CF test in 22.

Abattoirs↗
PubMed1976

The specificity and sensitivity of the fluorescent antibody test in cattle experimentally infected with Mycobacterium avium and Mycobacterium johnei.

In five calves experimentally infected with Mycobacterium avium and in 10 with M johnei it was shown that the serological response by the fluorescent antibody (FA) test was specific. The serological response in the M avium infected calves was transitory and lasted up to five months. The first evidence of a serological response with the FA test in the M johnei dosed calves occurred at four months, and all calves had reacted by nine months after dosing. At the 23 tests carried out between four and 32 months after dosing, when the experiment was terminated, an average of 5-8 animals was positive at any one test. Johne's disease was confirmed bacteriologically and histologically in six of the 10 calves though none had shown clinical signs.

Animals↗
PubMed1975

The effect of continuous doses of Trichostrongylus colubriformis larvae on the intestinal mucosa of sheep and on liver vitamin A concentration.

Eight 7-month-old sheep were dosed continuously with Trichostrongylus colubriformis larvae and 4 sheep were killed at 5 and 10 weeks from the commencement of infection. Flattening of the mucosa and villous atrophy were commonly present at slaughter, and parasites were often found in superficial channels parallel with the luminal surface. At 10 weeks the mucosa was thickened and highly cellular. Leucine aminopeptidase, alkaline phosphatase and maltase activity were reduced in the proximal third of the small intestine. Liver vitamin A was reduced in 3 of 4 infected sheep at 10 weeks, but serum vitamin A levels were comparable with those of worm-free control sheep throughout the experiment.

Alkaline Phosphatase↗
PubMed1975

Experimental infection of lambs with an aerosol of Pasteurella haemolytica.

Specific pathogen free lambs were exposed to an aerosol of Pasteurella haemolytica. Ten lambs vaccinated with an adjuvanted killed P haemolytica vaccine and nine units of P haemolytica administered in an aerosol. Pneumonia histologically indistinguishable from natural pneumonic pasteurellosis occurred in one vaccinated lamb and in four control lambs.

Adjuvants, Immunologic↗