Seventy-eight bovine viral diarrhoea viruses (BVDV) recently collected in Austria, France, Hungary, Italy, Slovakia, Spain and UK were genetically typed in the 5'-untranslated (5'UTR) and autoprotease (Npro) regions of the pestivirus genome. Seventy-six of the isolates were BVDV-1 and two French isolates were of the BVDV-2 genotype. Phylogenetic analysis of the 5'UTR (245 nt), including additional BVDV-1 sequences from USA, Canada, Germany, New Zealand, Mozambique and Sweden, taken from GenBank and from our previous works, indicated that these viruses were clustered not only into the two generally accepted groups (BVDV-1a-"NADL like" and BVDV-1b-"Osloss like"), but altogether into 11 phylogenetic groups. Similar clustering was observed with Npro region sequences (385 nt) and the highest bootstrap values (over 95%) were obtained by phylogeny combining 5'UTR and Npro sequences. Some associations between the genetic grouping and the origin of the isolates were apparent, probably reflecting historical trade contacts. Considering the variability of isolates it is recommended that diagnostic PCR primers should be re-examined to ensure coverage of all BVDV-1 groups. The genogroups were less clearly differentiated by monoclonal antibody typing, suggesting significant antigenic similarities within the BVDV-1 genotype.

By analysing the nucleotide sequence data generated from both the E2 (gp55) and the NS5B genes of classical swine fever virus (CSFV), in addition to previously published data from the 5'NCR, we were able to divide 115 CSFV isolates into two major groups, five subgroups and two disparate isolates. Further discrimination was possible by analysis of sequence data from the E2 region. The three sequencing based methods were compared to monoclonal antibody (MAb) typing and to limited restriction enzyme (RE) mapping. Although both MAb and RE methods confirmed the previous classification the resolution was inferior. We estimated an approximate evolution rate for CSFV from an analysis of the virus variation observed in a single geographical area over a 6 year period. Applying this proposed rate to each of our deduced CSFV subgroups enabled us to calculate the approximate dates of divergence for each subgroup.

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International audienceAvailable empirical data on the natural occurrence of ruminant pestiviruses has shown that bovine viral diarrhoea virus (BVDV) is nearly exclusively found in cattle, whereas both border disease virus (BDV) and BVDV can be isolated from sheep. During routine genetic typing of pestivirus RNA from UK cattle diagnosed as BVDV positive between 2006 and 2008, five samples that were classified as BDV positive yielded positive virus isolates in cell cultures. The samples originated from animals that had shown signs typical for BVD. Phylogenetic analysis of the bovine BDVs showed that two belonged to the BDV-1a group and three to the BDV-1b group, thereby matching the genetic diversity seen for previously described UK ovine BDVs. Antigenic typing with a set of monoclonal antibodies (MABs) showed that all bovine BDVs lacked one or more epitopes conserved among ovine BDV-1 isolates, and that they had gained reactivity with at least one BVDV-1 specific MAB. Serial passaging of two of the virus isolates in ovine cell cultures did not change the epitope expression pattern. These findings suggest that the presumed natural resistance of cattle against infection with BDV no longer holds. A consequence of this is that BVD diagnostic assays should be checked for their ability to also detect BDV, and also highlights the need for monitoring of the BDV status in sheep that may be in contact with cattle in areas with organised BVD control programmes

An RT-PCR method was developed that amplified genetic material from the 5' end of the S protein gene of both transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV), but discriminated between the two by the size of the product generated. A number of restriction endonuclease enzymes were assessed for recognition of the amplicons so produced. The assay was shown to detect viral RNA from all of the 26 different TGEV and PRCV isolates examined, covering a period from 1946 to 1996. Detection of TGEV in clinical specimens was possible using a spin column method to extract RNA and sensitivity was compared to virus isolation and antigen detection ELISA. The method could provide a means of confirming positive results from immunological screening tests such as FAT and ELISA, reducing the need for virus isolation and convalescent serology.