SEGREGATION OF BOVINE VIRAL DIARRHEA VIRUS INTO GENOTYPES

Isolates of bovine viral diarrhea virus (BVDV) were segregated into tw o groups based on comparison of sequences from the 5' untranslated reg ion (UTR) of the viral genome. Phylogenic analysis suggested that thes e groups, termed BVDV I and BVDV II, are as different from each other as reference BVDV (BVDV-NADL, BVDV-SD-1, BVDV-Osloss) are from hog cho lera virus. Polymerase chain reaction (PCR) tests, based on the 5' unt ranslated region and the genomic region coding for the p125 polypeptid e, were designed to differentiate between BVDV I and BVDV II. Using th ese tests, 76 of 140 isolates of BVDV were identified as BVDV II. Anti genic and pathologic differences were noted between BVDV I and BVDV II viruses. Among BVDV I were viruses commonly used in vaccine productio n, diagnostic tests, and research. BVDV II was isolated predominantly from fetal bovine sera, persistently infected calves born to dams vacc inated against BVDV, and cattle that had died from an acute form of BV DV termed hemorrhagic syndrome.