Experimental transmission of sheep-associated malignant catarrhal fever from sheep to Japanese deer (Cervus nippon) and cattle

The assumption that sheep carry ovine herpesvirus-2 (OvHV-2), the causative agent of sheep-associated malignant catarrhal fever (SA-MCF), is widely ac cepted, albeit OvHV-2 has not been isolated. We attempted experimental cont act transmission of MCF from Japanese sheep persistently infected with OvHV -2 to Japanese deer (Cervus nippon) and cattle. In Experiment 1, a deer was kept in close quarters with an infected ewe. In Experiment 2, a second dee r was kept with the same ewe. In Experiment 3, two cows were each kept with two infected wethers. In Experiment 1, the deer developed clinical signs a t 138 days after first contact and then died. OvHV-2 genes by polymerase ch ain reaction (PCR) and fluorescent antibodies to Alcelaphine herpesvirus-1 were detected in the affected deer. Moreover, sequences of PCR products (42 3 bp), obtained by amplification of materials from the sheep and from the a ffected deer, coincided. These results clearly confirmed that the sheep was a carrier of OvHV-2, and that this virus had induced SA-MCF in a deer. In other experiments, no OvHV-2 infection occurred in deer and cattle during t he 6-18 months periods of contact, though viral genes were detected in the nasal swabs and white blood cells of the sheep. To our knowledge, this is t he first report on successful experimental transmission of MCF from OvHV-2- infected sheep to deer. (C) 2001 Elsevier Science B.V. All rights reserved.