title: Evidence of widespread natural recombination among field isolates of equine herpesvirus 4 but not among field isolates of equine herpesvirus 1.
abstract: Recombination in alphaherpesviruses allows evolution to occur in viruses that have an otherwise stable DNA genome with a low rate of nucleotide substitution. High-throughput sequencing of complete viral genomes has recently allowed natural (field) recombination to be studied in a number of different alphaherpesviruses, however, such studies have not been applied to equine herpesvirus 1 (EHV-1) or equine herpesvirus 4 (EHV-4). These two equine alphaherpesviruses are genetically similar, but differ in their pathogenesis and epidemiology. Both cause economically significant disease in horse populations worldwide. This study used high-throughput sequencing to determine the full genome sequences of EHV-1 and EHV-4 isolates (11 and 14 isolates, respectively) from Australian or New Zealand horses. These sequences were then analysed and examined for evidence of recombination. Evidence of widespread recombination was detected in the genomes of the EHV-4 isolates. Only one potential recombination event was detected in the genomes of the EHV-1 isolates, even when the genomes from an additional 11 international EHV-1 isolates were analysed. The results from this study reveal another fundamental difference between the biology of EHV-1 and EHV-4. The results may also be used to help inform the future safe use of attenuated equine herpesvirus vaccines.
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: P K
authors.initials: PK
authors.lastname: Vaz
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Horsington
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: C A
authors.initials: CA
authors.lastname: Hartley
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: G F
authors.initials: GF
authors.lastname: Browning
authors.affiliation: Centre for Equine Infectious Diseases, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: N P
authors.initials: NP
authors.lastname: Ficorilli
authors.affiliation: Centre for Equine Infectious Diseases, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: M J
authors.initials: MJ
authors.lastname: Studdert
authors.affiliation: Centre for Equine Infectious Diseases, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: J R
authors.initials: JR
authors.lastname: Gilkerson
authors.affiliation: Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Devlin
mesh_terms: D000818:Animals; D001483:Base Sequence; D016679:Genome, Viral; D006566:Herpesviridae Infections / Q000662:veterinary* / Q000821:virology; D004861:Herpesvirus 1, Equid / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D023141:Herpesvirus 4, Equid / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006734:Horse Diseases / Q000821:virology*; D006736:Horses; D008969:Molecular Sequence Data; D009520:New Zealand; D010802:Phylogeny; D011995:Recombination, Genetic