Malignant catarrhal fever: polymerase chain reaction survey for ovine herpesvirus 2 and other persistent herpesvirus and retrovirus infections of dairy cattle and bison

Using a polymerase chain reaction (PCR) test for sequences of ovine herpesv irus 2 (OHV2), this virus was shown to be significantly associated with she ep-associated malignant catarrhal fever (SA-MCF) in terminal cases of disea se in 34 cattle and 53 bison. Ovine herpesvirus 2 was not detected in cattl e (38) and bison (10) that succumbed to other diseases. Other persistent he rpesviruses, retroviruses, and pestivirus, some of which have been previous ly isolated from cases of SA-MCF, were not associated with the disease. The se included bovine herpesvirus 4 (BHV4), bovine lymphotrophic herpesvirus ( BLHV), bovine syncytial virus (BSV, also known as bovine spumavirus), bovin e immunodeficiency virus (BIV), and bovine viral diarrhea virus (BVDV). A P CR survey for OHV2 in DNA from individual cow's peripheral blood lymphocyte s in 4 dairies showed that the 1 dairy that was in close contact to sheep h ad a prevalence of OHV2 of 21.3%, whereas the 3 other dairies had no OHV2. Prevalence of the other herpesviruses and retroviruses in the dairy cows wa s variable, ranging from 2% to 51% for BHV4, 52% to 78.7% for BLHV, and 10% to 34% for BSV. Bovine lymphotrophic herpesvirus and BSV were also found i n a few (1-4 of 21 tested) cases of terminal SB-MCF, but BIV and BVDV were not found in either the dairy cows sampled, or in the cases of SA-MCF. No s ignificant correlation was found between the presence of any 2 viruses (OHV 2, BHV4, BLHV, BSV) in the dairy cows or terminal cases of SA-MCF.