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Title: Sheep-associated malignant catarrhal fever-like skin disease in a free-ranging bighorn sheep (Ovis canadensis), Alberta, Canada

item SLATER, OWEN - University Of Calgary
item KENNEDY-PETERS, JEANINE - Cornell University
item LEJEUNE, MANIGANDAN - University Of Calgary
item GUMMER, DAVID - Parks Canada, Banff National Park
item MACBETH, B - University Of Calgary
item WARREN, AMY - University Of Calgary
item JOSEPH, TOMY - Animal Health Centre
item Li, Hong
item Cunha, Cristina
item DUIGNAN, PÁDRAIG - University Of Calgary

Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2016
Publication Date: 10/17/2016
Citation: Slater, O.M., Kennedy-Peters, J., Lejeune, M., Gummer, D., Macbeth, B., Warren, A., Joseph, T., Li, H., Cunha, C.W., Duignan, P.J. 2016. Sheep-associated malignant catarrhal fever-like skin disease in a free-ranging bighorn sheep (Ovis canadensis), Alberta, Canada. Journal of Wildlife Diseases. 53(1):153-158.

Interpretive Summary: This article describes a malignant catarrhal fever-like disease in a free-ranging bighorn sheep in Alberta, Canada. In July 2015, an adult female bighorn sheep was found with marked weight loss, muscle atrophy, and generalized skin lesions and was euthanized. Several diagnostic techniques were used to investigate pathogens present in skin lesions and the only one found was Ovine herpesvirus 2 (OvHV-2). Although OvHV-2 can be carried asymptotically by bighorn sheep, the increased levels of viral DNA found in skin lesion suggested that the virus might have played a role in the development of the lesions. Concurrent parasitic and bacterial infections identified in internal organs may have suppressed the BHS’s immune system enough to allow activation of the latent OvHV-2, leading to the chronic skin lesions. To our knowledge, this case represents the first report of OvHV-2 infection causing a skin lesions in a free-ranging bighorn sheep and illustrates that OvHV-2 should be a differential for dermatological diseases in BHS populations.

Technical Abstract: Malignant catarrhal fever (MCF)-like clinical disease was diagnosed in a free-ranging bighorn sheep (Ovis canadensis) in Alberta, Canada. Ante-mortem observations and gross pathology included muscle atrophy, marked weight loss and focally extensive alopecia with chronic crusting hyperkeratotosis and hypermelanosis of the head, inner ears, distal limbs, hip, perineal area and tail. Histologically, the skin lesions were characterized by mixed lymphocytic, eosinophilic and granulomatous mural folliculitis and furunculosis, dermatitis and epidermitis with multi-level epidermal apoptosis, compact ortho- and para-keratotic hyperkeratosis, and intraepithelial pustules consistent with previous reports of chronic Ovine herpesvirus-2 (OvHV-2) infection. Multiple skin samples were positive for OvHV-2 DNA on polymerase chain reaction (PCR), and on partial sequencing of the viral DNA, there was 94% homology with reference GenBank OvHV-2. Quantitative PCR confirmed an increased level of OvHV-2 DNA in the lesional skin tissues. Based on exclusion of other disease processes, gross and histological lesions, PCR and viral DNA sequencing results, a diagnosis of OvHV-2 mediated MCF-like dermatitis was made. We believe this to be the first description of OvHV-2 associated with clinical disease in bighorn sheep.