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Title: Studies on the role of parainfluenza virus type 3 and adenovirus in respiratory disease of sheep
Author: Sharp, James Michael
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1977
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Investigations were undertaken to isolate viruses from sheep, and to assess their role in respiratory diseases by means of epidemiological observations and experimental studies of their pathogenesis. Viruses were isolated from 0.7 per cent of samples taken at necropsies and from 16 per cent of sheep in 3 of 4 flocks currently affected with respiratory disease, but not from 7 flocks with few or no signs of clinical illness. An adenovirus was isolated from rectal swabs from lambs with respiratory disease. It was shown to differ from all known mammalian adenoviruses and was designated ovine adenovirus type 4 (OA4). Neutralizing antibodies to ovine adenovirus types 1-4 were frequently present in sheep sera and were more prevalent in animals over 12 months of age. Following exposure of specific pathogen-free (SPF) lambs to an aerosol of OA4 virus, replication of the virus occurred in the respiratory and alimentary tracts and liver, and neutralizing antibodies were found in the serum and nasal secretions as early as 8 days after inoculation. Infection was associated with a mild clinical illness, accompanied by pulmonary oedema, peribronchiolar accumulations of mononuclear cells in the lungs, and focal necrosis, lymphangitis and occlusive cholangitis in the liver. The clinical disease and pneumonic lesions observed in SPF lambs infected with both OA4 virus and Pasteurella haemolytica were no more severe than those in lambs infected with P. haemolytica alone. Enzootic pneumonia was induced consistently in SPF lambs inoculated with parainfluenza virus type 3 (P13) followed by P. haemolytica 4 or 7 days later. Seventy-eight per cent of lambs developed severe respiratory disease by this method, 54 per cent died and 95 per cent had macroscopic lung lesions. The illness and lesions were more marked in lambs inoculated with both P13 virus and P. haemolytica than in lambs inoculated with either agent alone, and were associated with rapid multiplication of P. haemolytica within the lungs.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available