GENETIC-CHARACTERIZATION OF RUMINANT PESTIVIRUSES - SEQUENCE-ANALYSISOF VIRAL GENOTYPES ISOLATED FROM SHEEP

Historically, the genus pestivirus was believed to contain three speci es of viruses; bovine viral diarrhea Virus (BVDV), border disease Viru s (BDV) and classical swine fever virus (CSFV). However, based on limi ted sequence analysis of a small number of pestiviral isolates from do mestic livestock, evidence has recently emerged indicating that at lea st four distinct genotypes exist. In an attempt to gain a better under standing of the degree of viral variation among ruminant pestiviruses, the entire structural gene coding region of an ovine pestivirus, BD31 , genome encompassing 3358 nucleotides was cloned and sequenced. Seque nce analysis revealed that BD31 shares less than 71% nucleotide simila rity with other pestiviruses, suggesting that BD31 is distinct from BV DV, CSFV as well as other ovine and bovine pestiviruses currently refe rred to as BVDV type II. Based on this data, BD31 is the first North A merican pestivirus isolate that falls under the category 'true BDV'. R esults from the analysis of the nucleotide sequence of the E0-E1 codin g region of six additional ruminant pestiviruses identified the existe nce of three distinct virus genotypes in North America. Thus, among ru minent pestiviruses, bovine isolates can be grouped into two genotypes , namely types 1 and 4, whereas ovine isolates fall into genotypes 1, 3 and 4. (C) 1997 Elsevier Science B.V.