Ovine herpesvirus-2 glycoprotein B sequences from tissues of ruminant malignant catarrhal fever cases and healthy sheep are highly conserved

Department of Pathology, Colorado State University, Fort Collins, CO 80523, USA 1 USDA, ARS, Arthropod-borne Animal Diseases Research Laboratory, Laramie, WY 82071-3965, USA 2 Department of Veterinary Science and Microbiology, University of Arizona, Tucson, AZ 85721-0090, USA 3 Author for correspondence: Magdalena Dunowska. Fax +1 970 491 0603. e-mail mdunowsk{at}lamar.colostate.edu Ovine herpesvirus-2 (OHV-2) infection has been associated with malignant catarrhal fever (MCF) in susceptible ruminants. In order to further investigate whether OHV-2 is an aetiological agent for sheep-associated (SA) MCF in cattle and bison, the entire sequences of OHV-2 glycoprotein B (gB) from different sources of viral DNA were compared. Target DNA was derived from tissues of bovine and bison cases of SA-MCF, from a lymphoblastoid cell line established from another bovine case of SA-MCF, and from a healthy sheep. The divergence between deduced amino acid sequences of OHV-2 gB ranged from 0·5 to 1·2%. The high degree of similarity between gB sequences from a healthy sheep and clinical cases of SA-MCF in cattle and bison suggests that OHV-2 is an ovine virus that is occasionally transmitted to other ruminant species, in which it can cause severe disease.