Presumptive protozoan (sarcocystis) encephalomyelitis with paresis in lambs.
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Animals↗
Biomedical subjects
M Jeffrey
Publications and source records attributed to M Jeffrey.
Possible role of leptospires of the Pomona serogroup in sporadic bovine abortion in the south west of England.
An investigation of a small outbreak of abortion in mixed-age cows in a dairy herd in Somerset produced circumstantial evidence that a leptospire belonging to the Pomona serogroup was the causative agent. Although the initial epidemic involved more than 30 per cent of the herd, agglutination titres did not persist in the majority of animals and bacteriological monitoring produced no evidence that this leptospire could establish endemic infection in dairy cattle. An isolate recovered from the kidney of a cow which aborted was found to be similar to mozdok, a serovar maintained by free-living species in continental Europe, and it is probable that free-living species also maintain the Pomona serogroup organisms that have been isolated in England. Clinical disease caused by infection of domestic stock with Pomona serogroup organisms other than pomona has not been recognised in other countries but this may be because of the presence of endemic infection with pomona, a serovar that causes a very similar clinical and serological response.
Abortion, Veterinary↗
Isolation of a syncytium-forming virus from a goat with polyarthritis.
Virus particles, morphologically indistinguishable from maedi-visna virus or caprine arthritis-encephalitis virus, were detected in tissue explant cultures prepared post mortem from a goat with joint, lung and kidney lesions similar to those associated with the caprine arthritis-encephalitis complex. Serum from this goat and others in its herd of origin gave positive reactions in an agar gel immunodiffusion test for maedi-visna virus antibodies.
Animals↗
PrP in pathology and pathogenesis in scrapie-infected mice.
PrP accumulation in the brains of mice infected with scrapie takes several different forms: amyloid plaques, widespread accumulation in neuropile, and perineuronal deposits. PrP is also sometimes detected within microglia and in or around astrocytes. There are dramatic and reproducible differences between scrapie strains in the relative prominence of these changes and their distribution in the brain. Depending on the scrapie strain, PrP pathology is targeted precisely to particular brain areas, often showing a clear association with identifiable groups of neurons. These results suggest that PrP changes are primarily associated with neurons, and that different scrapie strains recognize and selectively replicate in different populations of neurons. Immunostaining at the ultrastructural level demonstrates an association of PrP with neurite plasmalemma, around amyloid plaques, and in areas of widespread neuropile and perineuronal accumulation. It is probable that PrP is encoded by the Sinc gene, which controls the incubation period of scrapie in mice. Studies using the intraocular infection route show that the Sinc gene controls the onset rather than the rate of replication, suggesting that PrP may be involved in cell-to-cell spread of infection. The accumulation of PrP at the surface of neurons is consistent with such a role.
Animals↗
Early loss of neurons and axon terminals in scrapie-affected mice revealed by morphometry and immunocytochemistry.
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Animals↗
Arthropathy associated with Brucella abortus strain 19 vaccination in cattle. I. Examination of field cases.
Thirty cows presenting with lameness and persistent serological reactions to Brucella abortus had chronic granulomatous arthropathy of the femorotibial and occasionally other joints. Attempts to culture Brucella or other pathogens gave negative results but organisms of Brucella morphology were seen in fluorescent antibody-stained cryostat sections of synovial tissue. The synovial fluids contained high titres of antibodies to B. abortus and Yersinia enterocolitica O:9 and had elevated total protein and immunoglobulin concentrations showing an oligoclonal electrophoretic profile. Immune complexes and rheumatoid factor were detected in some of the fluids.
Animals↗
Arthropathy associated with Brucella abortus strain 19 vaccination in cattle. II. Experimental studies.
Attempts to reproduce in calves the arthropathy associated with Brucella abortus strain 19 (S19) vaccination by direct intra-articular injection of S19 or virulent Brucella cells were unsuccessful. Intra-articular injection of rabbits and a calf with immune complexes isolated from the synovial fluid of a field case produced clinical and histological signs of arthropathy accompanied by the development of rheumatoid factor.
Animals↗
Murine scrapie infection causes an abnormal germinal centre reaction in the spleen.
Follicular dendritic cells (FDCs) of the lymphoreticular system play a role in the peripheral replication of prion proteins in some transmissible spongiform encephalopathies (TSEs), including experimental murine scrapie models. Disease-specific PrP (PrPd) accumulation occurs in association with the plasmalemma and extracellular space around FDC dendrites, but no specific immunological response has yet been reported in animals affected by TSEs. In the present study, morphology (light microscopical and ultrastructural) of secondary lymphoid follicles of the spleen were examined in mice infected with the ME7 strain of scrapie and in uninfected control mice, with or without immunological stimulation with sheep red blood cells (SRBCs), at 70 days post-inoculation or at the terminal stage of disease (268 days). Scrapie infection was associated with hypertrophy of FDC dendrites, increased retention of electron-dense material at the FDC plasma membrane, and increased maturation and numbers of B lymphocytes within secondary follicles. FDC hypertrophy was particularly conspicuous in immune-stimulated ME7-infected mice. The electron-dense material was associated with PrP Napoli accumulation, as determined by immunogold labelling. We hypothesize that immune system changes are associated with increased immune complex trapping by hypertrophic FDCs expressing PrP Napoli molecules at the plasmalemma of dendrites, and that this process is exaggerated by immune system stimulation. Contrary to previous dogma, these results show that a pathological response within the immune system follows scrapie infection.
Animals↗
Multifocal ischaemic encephalomyelopathy associated with fibrocartilaginous emboli in the lamb.
Multifocal, arterial, fibrocartilaginous embolism of the cervical spinal cord, medulla oblongata and cerebellum is described in a neonatal lamb. The emboli contained mucosubstances which, by the Alcian blue critical electrolyte concentration method, were identified as mainly keratan sulphate. This composition indicates the probable origin of emboli from the nucleus pulposus of intervertebral discs. Possible modes of entry of such material into the spinal cord vasculature are reviewed and a mechanism proposed to explain the localization of emboli in spinal cord, brain stem and cerebellar arteries in this case.
Animals↗