title: A European field strain of bluetongue virus derived from two parental vaccine strains by genome segment reassortment.
abstract: Since 1998, nine bluetongue virus (BTV) strains from serotypes 1, 2, 4, 8, 9 and 16 have invaded Europe, killing >2 million animals (mainly sheep). Live vaccine strains of BTV-2, 4, 9 and 16 have also been used in the region. The BTV genome is composed of ten linear-segments of dsRNA, and events in Europe have provided opportunities for different strains to exchange/reassort genome segments, generating novel progeny-viruses. Genome segment 2 (Seg-2) encodes outer capsid protein VP2, the primary determinant of virus serotype, while Seg-5 encodes NS1, which forms 'tubules' within the cell-cytoplasm. Seg-2 and Seg-5 from 15 European isolates, and vaccine/reference strains, of BTV-2 and BTV-16, were sequenced. Isolates from the same serotype showed >92% nt identity in Seg-5, but <84% identity between types. However, published data for Seg-5 of BTV-16 from Italy 2002 showed <83% nt identity with other BTV-16 strains, but was identical to the BTV-2 vaccine strain (used in Italy during 2002, and annually in a multivalent vaccine in Israel since 1995) indicating that ITL2002 is a reassortant between the BTV-2 and BTV-16 vaccine strains. This represents the first detection of a reassortant BTV strain within Europe, highlighting concerns about the use of live BTV vaccines in the region.
authors.affiliation: Arbovirus Research Group, Institute for Animal Health, Ash Road, Pirbright, UK. carrie.batten@bbsrc.ac.uk
authors.forename: Carrie A
authors.initials: CA
authors.lastname: Batten
authors.forename: Sushila
authors.initials: S
authors.lastname: Maan
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Shaw
authors.forename: Narender S
authors.initials: NS
authors.lastname: Maan
authors.forename: Peter P C
authors.initials: PP
authors.lastname: Mertens
mesh_terms: D000818:Animals; D001819:Bluetongue / Q000517:prevention & control / Q000821:virology*; D001820:Bluetongue virus / Q000235:genetics* / Q000302:isolation & purification; D005060:Europe; D016679:Genome, Viral / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016865:Reassortant Viruses / Q000235:genetics* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D012703:Serotyping; D012756:Sheep; D014765:Viral Vaccines / Q000235:genetics*
chemical_list: D014765:Viral Vaccines