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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Endemic Poultry Viral Diseases Research » Research » Publications at this Location » Publication #344267

Research Project: Genetic and Biological Determinants of Avian Herpesviruses Pathogenicity, Transmission, and Evolution to Inform the Development of Effective Control Strategies

Location: Endemic Poultry Viral Diseases Research

Title: Genetic diversity of infectious laryngotracheitis virus during in vivo coinfection parallels viral replication and arises from recombination hot spots within the genome

item LONCOMAN, CARLOS - University Of Melbourne
item HARTLEY, CAROL - University Of Melbourne
item COPPO, MAURICIO J - University Of Melbourne
item VAZ, PAOLA - University Of Melbourne
item DIAZ-MENDEZ, ANDREAS - University Of Melbourne
item BROWNING, GLENN - University Of Melbourne
item GARCIA, MARICARMEN - University Of Georgia
item Spatz, Stephen
item DEVLIN, JOANNE - (NCE, CECR)networks Of Centres Of Exellence Of Canada, Centres Of Excellence For Commercilization A

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2017
Publication Date: 9/22/2017
Publication URL:
Citation: Loncoman, C.A., Hartley, C.A., Coppo, M.C., Vaz, P.K., Diaz-Mendez, A., Browning, G.F., Garcia, M., Spatz, S.J., Devlin, J.M. 2017. Genetic diversity of infectious laryngotracheitis virus during in vivo coinfection parallels viral replication and arises from recombination hot spots within the genome. Applied and Environmental Microbiology. 83(23):e01532-17.

Interpretive Summary: Recombination of infectious laryngotracheitis virus strains can be demonstrated in infected chickens. Recombination is linked to virus DNA replication and there are regions in the virus genome that mediate this recombination.

Technical Abstract: Recombination is a feature of many alphaherpesviruses that infect people and animals. Infectious laryngotracheitis virus (ILTV; Gallid alphaherpesvirus 1) causes respiratory disease in chickens, resulting in significant production losses in poultry industries worldwide. Natural (field) ILTV recombination is widespread, particularly recombination between attenuated ILTV vaccine strains to create virulent viruses. These virulent recombinants have had a major impact on animal health. Recently, the development of a single nucleotide polymorphism (SNP) genotyping assay for ILTV has helped to understand ILTV recombination in laboratory settings. In this study, we applied this SNP genotyping assay to further examine ILTV recombination in the natural host. Following coinoculation of specific-pathogen-free chickens, we examined the resultant progeny for evidence of viral recombination and characterized the diversity of the recombinants over time. The results showed that ILTV replication and recombination are closely related and that the recombinant viral progeny are most diverse 4 days after coinoculation, which is the peak of viral replication. Further, the locations of recombination breakpoints in a selection of the recombinant progeny, and in field isolates of ILTV from different geographical regions, were examined following full-genome sequencing and used to identify recombination hot spots in the ILTV genome. IMPORTANCE Alphaherpesviruses are common causes of disease in people and animals. Recombination enables genome diversification in many different species of alphaherpesviruses, which can lead to the evolution of higher levels of viral virulence. Using the alphaherpesvirus infectious laryngotracheitis virus (ILTV), we performed coinfections in the natural host (chickens) to demonstrate high levels of virus recombination. Higher levels of diversity in the recombinant progeny coincided with the highest levels of virus replication. In the recombinant progeny, and in field isolates, recombination occurred at greater frequency in recombination hot spot regions of the virus genome. Our results suggest that control measures that aim to limit viral replication could offer the potential to limit virus recombination and thus the evolution of virulence. The development and use of vaccines that are focused on limiting virus replication, rather than vaccines that are focused more on limiting clinical disease, may be indicated in order to better control disease.