Attenuated vaccines can recombine to form virulent field viruses.
Recombination between herpesviruses has been seen in vitro and in vivo under experimental conditions. This has raised safety concerns about using attenuated herpesvirus vaccines in human and veterinary medicine and adds to other known concerns associated with their use, including reversion to virulence and disease arising from recurrent reactivation of lifelong chronic infection. We used high-throughput sequencing to investigate relationships between emergent field strains and vaccine strains of infectious laryngotracheitis virus (ILTV, gallid herpesvirus 1). We show that independent recombination events between distinct attenuated vaccine strains resulted in virulent recombinant viruses that became the dominant strains responsible for widespread disease in Australian commercial poultry flocks. These findings highlight the risks of using multiple different attenuated herpesvirus vaccines, or vectors, in the same populations.
Asia-Pacific Centre for Animal Health, Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
Sang-Won
SW
Lee
Philip F
PF
Markham
Mauricio J C
MJ
Coppo
Alistair R
AR
Legione
John F
JF
Markham
Amir H
AH
Noormohammadi
Glenn F
GF
Browning
Nino
N
Ficorilli
Carol A
CA
Hartley
Joanne M
JM
Devlin
D000818:Animals; D002645:Chickens; D004279:DNA, Viral / Q000235:genetics; D016679:Genome, Viral; D006566:Herpesviridae Infections / Q000662:veterinary* / Q000821:virology; D001352:Herpesvirus 1, Gallid / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology; D022283:Herpesvirus Vaccines; D059014:High-Throughput Nucleotide Sequencing; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D011201:Poultry Diseases / Q000821:virology*; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D013047:Specific Pathogen-Free Organisms; D014613:Vaccines, Attenuated; D014774:Virulence; D014779:Virus Replication
D004279:DNA, Viral; D022283:Herpesvirus Vaccines; D014613:Vaccines, Attenuated