|O'TOOLE, DONAL - Wyoming State Veterinary Laboratory|
|CUNHA, CRISTINA - Washington State University|
|WARG, JANET - Diagnostic Virology Laboratory/ National Veterinary Services Laboratories|
|BROOKING, ANGELA - Mill Creek Veterinary Hospital|
Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2014
Publication Date: 4/13/2014
Citation: Taus, N.S., O'Toole, D., Herndon, D.R., Cunha, C.W., Warg, J.V., Seal, B.S., Brooking, A., Li, H. 2014. Malignant catarrhal fever in American bison (Bison bison) experimentally infected with alcelaphine herpesvirus 2. Veterinary Microbiology. DOI:10.1016/j.vetmic.2014.04.003.
Interpretive Summary: Appreciable death loss in ranched bison throughout North America results from malignant catarrhal fever (MCF) caused by ovine herpesvirus-2 (OvHV-2). A vaccine is urgently needed by producers to protect their stock. Because OvHV-2 cannot currently be grown in cell culture, it is not possible to attenuate it for use as a modified live vaccine. One strategy to overcome this barrier is to use a related virus, which can be grown in culture and which does not cause disease, as a vehicle to carry genes from OvHV-2 that stimulate a protective immune response. Alcelaphine herpesvirus-2 (AlHV-2) is a candidate virus to develop into such a vector; it can be grown in cell culture and has not been reported to cause disease. Six bison were inoculated with AlHV-2 via the airway or into the muscle. All six animals were infected and three of them developed MCF. Thus AlHV-2 is not suitable as a vaccine vector without first being modified so that it does not cause disease in bison.
Technical Abstract: Malignant catarrhal fever (MCF) due to ovine herpesvirus-2 (OvHV-2) causes appreciable death loss in ranched bison (Bison bison) throughout North America. No vaccine exists to protect animals from disease. Since OvHV-2 has not been propagated in vitro, one strategy to develop a modified live vaccine is to use a closely related but non-pathogenic member of the malignant catarrhal fever virus family as a vector to express protective OvHV-2 epitopes. Alcelaphine herpesvirus-2 (AlHV-2) derived from topi (Damaliscus lunatus) has not been reported to cause disease following experimental challenge. AlHV-2 was tested for its ability to infect and induce disease in American bison. Six yearling bison were inoculated intranasally (n = 3) or intramuscularly (n = 3) with 2 x10-4.7 TCID50 of AlHV-2, and monitored for infection and the development of disease. All six inoculated bison became infected with AlHV-2. Three of the six animals developed clinical signs and had gross and/or histological lesions consistent with MCF, which differed in distribution from those in bison with MCF due to OvHV-2. Unmodified AlHV-2 is an unsuitable vaccine vector for the prevention of MCF.