title: Genomic sequences of Australian bluetongue virus prototype serotypes reveal global relationships and possible routes of entry into Australia.
abstract: Bluetongue virus (BTV) is transmitted by biting midges (Culicoides spp.). It causes disease mainly in sheep and occasionally in cattle and other species. BTV has spread into northern Europe, causing disease in sheep and cattle. The introduction of new serotypes, changes in vector species, and climate change have contributed to these changes. Ten BTV serotypes have been isolated in Australia without apparent associated disease. Simplified methods for preferential isolation of double-stranded RNA (dsRNA) and template preparation enabled high-throughput sequencing of the 10 genome segments of all Australian BTV prototype serotypes. Phylogenetic analysis reinforced the Western and Eastern topotypes previously characterized but revealed unique features of several Australian BTVs. Many of the Australian BTV genome segments (Seg-) were closely related, clustering together within the Eastern topotypes. A novel Australian topotype for Seg-5 (NS1) was identified, with taxa spread across several serotypes and over time. Seg-1, -2, -3, -4, -6, -7, -9, and -10 of BTV_2_AUS_2008 were most closely related to the cognate segments of viruses from Taiwan and Asia and not other Australian viruses, supporting the conclusion that BTV_2 entered Australia recently. The Australian BTV_15_AUS_1982 prototype was revealed to be unusual among the Australian BTV isolates, with Seg-3 and -8 distantly related to other BTV sequences from all serotypes.
authors.affiliation: CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria, Australia. david.boyle@csiro.au
authors.forename: David B
authors.initials: DB
authors.lastname: Boyle
authors.forename: Dieter M
authors.initials: DM
authors.lastname: Bulach
authors.forename: Rachel
authors.initials: R
authors.lastname: Amos-Ritchie
authors.forename: Mathew M
authors.initials: MM
authors.lastname: Adams
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Walker
authors.forename: Richard
authors.initials: R
authors.lastname: Weir
mesh_terms: D000818:Animals; D001315:Australia; D001819:Bluetongue / Q000635:transmission / Q000821:virology*; D001820:Bluetongue virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D002417:Cattle; D002418:Cattle Diseases / Q000635:transmission / Q000821:virology*; D002460:Cell Line; D002519:Ceratopogonidae / Q000821:virology; D023281:Genomics; D007303:Insect Vectors / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D014764:Viral Proteins / Q000235:genetics
chemical_list: D014764:Viral Proteins