Using RNA purified directly from stored clinical specimens, a collection of
62 pestiviruses were typed by RT-PCR and sequencing within the 5'-untransl
ated region of the genome. All the specimens had been obtained in 1966/1967
from diary cattle in England and Wales. Eight further pestiviruses, grown
in cell culture, were characterised in the same way. Seven of these viruses
were representatives of a panel of British isolates, obtained from cattle
ten years before. The eighth was the virus used in a British bovine viral d
iarrhoea (BVD) vaccine. Most of the viruses were genetically unique and wer
e of BVDV type Ia. One recent isolate was BVDV type Ib, two others were int
ermediate between Ia and Ib, No BVDV type II or border disease virus (BDV)
isolates were found. There was no overall association between geographical
and phylogenetic clustering, suggesting long-distance virus dispersal, pres
umably via trading of infected cattle. The sequences of the recently obtain
ed cattle viruses were very similar or, in one case, identical to the older
isolates in the region studied. Their close similarity to some previously
characterised pestiviruses from British sheep suggests that a common pool o
f BVDV Ia is shared by these two livestock species, although another pestiv
irus - BVDV - is confined to sheep. The British cattle viruses were mostly
distinct from continental European isolates, but more similar to type Ia is
olates from North American cattle. Crown Copyright (C) 1999 Published by El
sevier Science B.V.