Sheep-Associated Malignant Catarrhal Fever–Like Skin Disease in a Free-Ranging Bighorn Sheep (Ovis canadensis), Alberta, Canada

Abstract

Malignant catarrhal fever-like clinical disease was diagnosed in a free-ranging bighorn sheep ( Ovis canadensis ) from Alberta, Canada, in June 2015. Antemortem and gross pathology findings included muscle atrophy, marked weight loss, and bilaterally symmetric alopecia with hyperpigmentation and crusting over the face, medial surfaces of the pinnae, dorsal trunk, distal limbs, perineal area, and tail. Histologically, the skin lesions were characterized by granulomatous mural folliculitis with numerous multinucleated giant cells and fewer lymphocytes and eosinophils consistent with previous reports of chronic ovine herpesvirus-2 (OvHV-2) infection. Multiple skin samples were positive for OvHV-2 DNA on 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 malignant catarrhal fever-like dermatitis was made.

Granulomatous mural folliculitis in 16 domestic goats: Infection with malignant catarrhal fever viruses and colocalization with ovine herpesvirus-2 using in situ hybridization

“…22,30 The cutaneous lesions observed in this case series had similar macroscopic characteristics between all 16 goats, and were consistent with previous reports of caprine GMF, 10,45 and GMF in other ruminant animal species. 4,11,24,28,44 Although reports of GMF in MCF-infected cattle are rare, other cutaneous lesions are relatively common as a part of the systemic disease process in classic vasculocentric MCF, and are increasingly prominent with greater chronicity. 4,24 Cutaneous lesions seen with typical chronic MCF in cattle feature many of the same gross characteristics described in this caprine GMF case series, such as crusting, alopecia, and erosion.…”

Phylogenetic analysis of ovine herpes virus-2 (OHV-2) in malignant catarrhal fever infected cattle in AL-Qadisiyah of Iraq

“…The disease forms range from acute severe inflammatory disease with a short clinical course to a more chronic syndrome occasionally with skin form (13). The summarized symptoms of MCF in cattle are marked with high fever, depression, anorexia, conjunctivitis, corneal opacity, lymphadenopathy, ulceration and erosions of the upper digestive and respiratory systems, and neurological disorders, in chronic cases weight loss, muscle atrophy and bilaterally symmetric alopecia (13,14).…”

High copy number of ovine gammaherpesvirus 2 DNA associated with malignant catarrhal fever–like syndrome in a lamb

“…7 Although there is a long-held belief that OvHV-2 does not cause disease in sheep, histologic lesions consistent with MCF have been observed occasionally in both domestic and wild sheep. 5,15 The fact that MCF-like disease can be induced in sheep by experimental inoculation of OvHV-2 suggests that MCF can also occur in sheep following natural infection. 9 Because almost all sheep have life-long infection with OvHV-2, detection of antibodies to OvHV-2 or viral DNA in a clinically affected sheep has little value to confirm the diagnosis of MCF.…”

“…A 2017 published report of a MCF-like skin disease in a free-ranging bighorn sheep, another natural OvHV-2 reservoir host, identified higher levels of OvHV-2 DNA in affected skin relative to unaffected skin. 15 In addition, studies in bison and rabbits with experimentally induced SA-MCF revealed that OvHV-2 DNA levels are positively correlated with lesion severity scores. 3,4 In order to determine if there was a similar association in the clinically affected lamb described in our study, tissue lesions were scored using a score criterion previously developed for bison with MCF.…”

“…7 Although there is a long-held belief that OvHV-2 does not cause disease in sheep, histologic lesions consistent with MCF have been observed occasionally in both domestic and wild sheep. 5,15 The fact that MCF-like disease can be induced in sheep by experimental inoculation of OvHV-2 suggests that MCF can also occur in sheep following natural infection. 9…”