Abstract
Gallid alphaherpesvirus 1 causes infectious laryngotracheitis (ILT) in farmed poultry worldwide. Intertypic recombination between vaccine strains of this virus has generated novel and virulent isolates in field conditions. In this study, in vitro and in ovo systems were co-infected and superinfected under different conditions with two genomically distinct and commonly used ILTV vaccines. The progeny virus populations were examined for the frequency and pattern of recombination events using multi-locus high-resolution melting curve analysis of polymerase chain reaction products. A varied level of recombination (0 to 58.9%) was detected, depending on the infection system (in ovo or in vitro), viral load, the composition of the inoculum mixture, and the timing and order of infection. Full genome analysis of selected recombinants with different in vitro phenotypes identified alterations in coding and non-coding regions. The ability of ILTV vaccines to maintain their capacity to recombine under such varied conditions highlights the significance of recombination in the evolution of this virus and demonstrates the capacity of ILTV vaccines to play a role in the emergence of recombinant viruses.
Highlights
Herpesviruses are an important cause of disease in a wide range of animal species, including production and companion animals
Recombination is a common event in Infectious laryngotracheitis virus (ILTV) infections [12, 14, 16, 17] and the results of this study support and extend previous studies by demonstrating the resilience of ILTV
We have shown that the A20 and Serva vaccine strains can recombine in both chick embryo kidney (CEK) cells and chicken embryos, generating intertypic recombinants under a wide range of conditions
Summary
Herpesviruses are an important cause of disease in a wide range of animal species, including production and companion animals. Infectious laryngotracheitis virus (ILTV; gallid alphaherpesvirus 1) is an alphaherpesvirus that causes acute respiratory tract disease in domestic poultry and results in significant economic losses worldwide [1, 2]. The economic losses caused by ILTV are due to the mortalities it causes, as well as its impact on the growth rate of broiler chickens, on egg production in layer farms, and on susceptibility to other respiratory pathogens [1]. Superinfection and recombination by infectious laryngotracheitis vaccine strains in vitro and in ovo controlling the outbreaks of disease [4]. Several recombinant or virally vectored vaccines are in use or development and include ILTVs with deletions of virulence-related open reading frames (ORFs) [5, 6], and fowl-pox virus (FPV) [7] and turkey herpesvirus (HVT) [8, 9] expressing specific ILTV glycoprotein genes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
