Intra-nasal inoculation of American bison (Bison bison) with ovine herpesvirus-2 (OvHV-2) reliably reproduces malignant catarrhal fever.
Sheep-associated malignant catarrhal fever (MCF) due to infection with ovine herpesvirus 2 (OvHV-2) is common in commercial herds of American bison ( Bison bison). Inability to propagate OvHV-2 in vitro has been a constraint on experimental studies of the disease. We sought to establish whether nasal secretions from sheep that shed OvHV-2 might induce the disease in bison and to define a minimum challenge dose. Fourteen bison were nebulized with sheep nasal sections containing 10(3)-10(7) OvHV-2 deoxyribonucleic acid (DNA) copies. Most challenged bison (11/14, 78.6%) developed clinical signs at 29-52 days postnebulization (DPN). The mean incubation time was 42.18 (+/-7.33 SD) DPN. Using real-time polymerase chain reaction, we detected OvHV-2 DNA in peripheral blood leukocytes at 21-31 DPN. All bison that developed MCF had antibodies against the MCF group viruses. Gross and histologic lesions were typical of the acute disease. There was no morphologic evidence of a dose-related difference in the severity or distribution of lesions. This is the first successful reproduction of MCF in bison using a nasal route of exposure. Experimentally challenged bison are more susceptible to MCF, compared with experimentally challenged domestic cattle in a previous experiment. Bison are a pertinent ruminant species in which the pathogenesis of the disease can be investigated.
O'Toole
D
D
Wyoming State Veterinary Laboratory, 1174 Snowy Range Road, Laramie, WY 82070, USA. DOT@uwyo.edu
Taus
N S
NS
Montgomery
D L
DL
Oaks
J L
JL
Crawford
T B
TB
Li
H
H
D000818:Animals; D016164:Bison / Q000821:virology*; D004198:Disease Susceptibility; D006564:Herpesviridae; D008168:Lung / Q000473:pathology; D008297:Male; D008304:Malignant Catarrh / Q000473:pathology / Q000821:virology*; D009297:Nasal Mucosa / Q000378:metabolism / Q000821:virology