Abstract
To date, recombination between different strains of the avian alphaherpesvirus infectious laryngotracheitis virus (ILTV) has only been detected in field samples using full genome sequencing and sequence analysis. These previous studies have revealed that natural recombination is widespread in ILTV and have demonstrated that recombination between two attenuated ILTV vaccine strains generated highly virulent viruses that produced widespread disease within poultry flocks in Australia. In order to better understand ILTV recombination, this study developed a TaqMan single nucleotide polymorphism (SNP) genotyping assay to detect recombination between two field strains of ILTV (CSW-1 and V1-99 ILTV) under experimental conditions. Following in vivo co-inoculation of these two ILTV strains in specific pathogen free (SPF) chickens, recovered viruses were plaque purified and subjected to the SNP genotyping assay. This assay revealed ILTV recombinants in all co-inoculated chickens. In total 64/87 (74%) of the recovered viruses were recombinants and 23 different recombination patterns were detected, with some of them occurring more frequently than others. The results from this study demonstrate that the TaqMan SNP genotyping assay is a useful tool to study recombination in ILTV and also show that recombination occurs frequently during experimental co-infection with ILTV in SPF chickens. This tool, when used to assess ILTV recombination in the natural host, has the potential to greatly contribute to our understanding of alphaherpesvirus recombination.
Highlights
Infectious laryngotracheitis virus (ILTV) causes mild to severe respiratory tract disease in chickens that results in major economic losses as a consequence of increase mortality and decreased weight gain and egg production in poultry industries worldwide [1]
Previous studies have shown that single nucleotide polymorphism (SNP) genotyping assays can be used to detect in vitro recombination between two closely related strains of the alphaherpesvirus bovine herpesvirus 1 (BHV-1) [27] but this is the first to apply this technique to the study of recombination in ILTV, and the first study to use this technique to study alphaherpesvirus recombination in the natural host
As herpesviruses have a long history of virus-host coevolution extending over 200 million years, studies performed in the natural host can reveal aspects of alphaherpesvirus biology that may not be apparent in studies that utilize laboratory animal models of infection [28]
Summary
Infectious laryngotracheitis virus (ILTV) causes mild to severe respiratory tract disease in chickens that results in major economic losses as a consequence of increase mortality and decreased weight gain and egg production in poultry industries worldwide [1]. ILTV vaccine strains in Australia [3] These new field strains have been responsible for widespread outbreaks of disease and have displaced previously dominant field strains in some regions in Australia [3,4,5]. Another virulent recombinant virus, class 10 ILTV, has emerged in Australia to become dominant in some poultry producing regions [6]. As alphaherpesviruses have a DNA polymerase with a highly efficient proofreading activity, these viruses have very low genetic mutation rates [13, 14] and so recombination can be important for herpesvirus genome diversification [3, 15, 16]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
