scholarly journals Analysis of Whole-Genome Sequences of Infectious laryngotracheitis Virus Isolates from Poultry Flocks in Canada: Evidence of Recombination

Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1302
Author(s):  
Ana Perez Contreras ◽  
Frank van der Meer ◽  
Sylvia Checkley ◽  
Tomy Joseph ◽  
Robin King ◽  
...  
Keyword(s):  
British Columbia ◽  
Phylogenetic Analysis ◽  
Vaccine Virus ◽  
Whole Genome ◽  
Wild Type ◽  
Genome Sequences ◽  
Infectious Laryngotracheitis Virus ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus ◽  
Recombination Breakpoints

Infectious laryngotracheitis virus (ILTV) is a herpes virus that causes an acute respiratory disease of poultry known as infectious laryngotracheitis (ILT). Chicken embryo origin (CEO) and tissue culture origin (TCO) live attenuated vaccines are routinely used for the control of ILT. However, vaccine virus is known to revert to virulence, and it has been recently shown that ILT field viral strains can undergo recombination with vaccinal ILTV and such recombinant ILT viruses possess greater transmission and pathogenicity potential. Based on complete or partial genes of the ILTV genome, few studies genotyped ILTV strains circulating in Canada, and so far, information is scarce on whole-genome sequencing or the presence of recombination in Canadian ILTV isolates. The objective of this study was to genetically characterize the 14 ILTV isolates that originated from three provinces in Canada (Alberta, British Columbia and Quebec). To this end, a phylogenetic analysis of 50 ILTV complete genome sequences, including 14 sequences of Canadian origin, was carried out. Additional phylogenetic analysis of the unique long, unique short and inverted repeat regions of the ILTV genome was also performed. We observed that 71%, 21% and 7% of the ILTV isolates were categorized as CEO revertant, wild-type and TCO vaccine-related, respectively. The sequences were also analyzed for potential recombination events, which included evidence in the British Columbia ILTV isolate. This event involved two ILTV vaccine (CEO) strains as parental strains. Recombination analysis also identified that one ILTV isolate from Alberta as a potential parental strain for a United States origin ILTV isolate. The positions of the possible recombination breakpoints were identified. These results indicate that the ILTV wild-type strains can recombine with vaccinal strains complicating vaccine-mediated control of ILT. Further studies on the pathogenicity of these ILTV strains, including the recombinant ILTV isolate are currently ongoing.

scholarly journals Genotyping of Infectious Laryngotracheitis Virus (ILTV) Isolates from Western Canadian Provinces of Alberta and British Columbia Based on Partial Open Reading Frame (ORF) a and b

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1634
Author(s):  
Catalina Barboza-Solis ◽  
Ana Perez Contreras ◽  
Victor A. Palomino-Tapia ◽  
Tomy Joseph ◽  
Robin King ◽  
...  
Keyword(s):  
British Columbia ◽  
Open Reading Frame ◽  
Nucleotide Polymorphisms ◽  
Wild Type ◽  
Infectious Laryngotracheitis Virus ◽  
Group V ◽  
Reading Frame ◽  
Transmission Potential ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus

Infectious laryngotracheitis virus (ILTV) causes an acute upper respiratory disease in chickens called infectious laryngotracheitis (ILT). Live attenuated vaccines are effective in disease control; however, they have residual virulence, which makes them able to replicate, cause disease and revert to the original virulent form. Information is scarce on the molecular nature of ILTV that is linked to ILT in Canada. This study aims to determine whether isolates originating from ILT cases in Western Canada are a wild type or vaccine origin. Samples submitted for the diagnosis of ILT between 2009–2018 were obtained from Alberta (AB, n = 46) and British Columbia (BC, n = 9). For genotyping, a Sanger sequencing of open reading frame (ORF) a and b was used. A total of 27 from AB, and 5 from BC samples yielded a fragment of 1751 base pairs (bp). Three of the BC samples classified as group IV (CEO vaccine strains) and 2 as group V (CEO revertant). Of the AB samples, 22 samples clustered with group V, 3 with group VI (wild type), and 2 with group VII, VIII, and IX (wild type). Overall, 17 non-synonymous single nucleotide polymorphisms (SNPs) were detected. Further studies are underway to ascertain the virulence and transmission potential of these isolates.

scholarly journals Transmission of infectious laryngotracheitis virus vaccine and field strains: the role of degree of contact and transmission by whole blood, plasma and poultry dust

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Addisu A. Yegoraw ◽  
Awol M. Assen ◽  
Priscilla F. Gerber ◽  
Stephen W. Walkden-Brown
Keyword(s):  
Direct Contact ◽  
Vaccine Virus ◽  
Wild Type ◽  
Airborne Transmission ◽  
Infectious Laryngotracheitis Virus ◽  
Infectious Laryngotracheitis ◽  
Poultry Dust ◽  
Laryngotracheitis Virus ◽  
Type Strains

AbstractUnderstanding the mechanisms of transmission of infectious laryngotracheitis virus (ILTV) is critical to proper control as both vaccine and wild-type strains circulate within chicken flocks with potential adverse consequences. The relative efficiency of transmission by direct contact between chickens and airborne transmission has not been investigated. Furthermore, relatively high levels of ILTV DNA have been detected in poultry dust and blood but the infectivity of these is unknown. In this study, comparison of in-contact and airborne transmission of two vaccine and one field strain of ILTV revealed that all transmitted to 100% of in-contact birds by 6 days post-exposure (dpe). Airborne transmission without contact resulted in 100% transmission by 14 and 17 dpe for the wild-type and Serva vaccine virus but only 27% transmission by 21 dpe for the A20 vaccine virus. The infectivity of dust or extracts of dust and blood or plasma from infected chickens at various stages of infection was assessed by inoculation into susceptible chickens. There was no transmission by any of these materials. In conclusion, direct contact facilitated efficient ILTV transmission but the virus was unable to be transmitted by dust from infected chickens suggestive of a limited role in the epidemiology of ILTV.

scholarly journals In Vitro and In Vivo Relevance of Infectious Laryngotracheitis Virus gJ Proteins That Are Expressed from Spliced and Nonspliced mRNAs

2005 ◽  
Vol 79 (2) ◽  
pp. 705-716 ◽  
Author(s):  
Walter Fuchs ◽  
Dorothee Wiesner ◽  
Jutta Veits ◽  
Jens P. Teifke ◽  
Thomas C. Mettenleiter
Keyword(s):  
Severe Disease ◽  
Progeny Virus ◽  
Wild Type ◽  
Infectious Laryngotracheitis Virus ◽  
Live Virus ◽  
Specific Antibodies ◽  
Field Virus ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus

ABSTRACT The positional homologue in the infectious laryngotracheitis virus (ILTV) genome of the glycoprotein gJ gene of herpes simplex virus and the gp2 gene of equine herpesvirus 1 is expressed into four proteins of 85, 115, 160, and 200 kDa (J. Veits, B. Köllner, J. P. Teifke, H. Granzow, T. C. Mettenleiter, and W. Fuchs, Avian Dis. 47:330-342, 2003). RNA analyses revealed that these proteins are expressed from two different late (γ2) transcripts, an unspliced 5.5-kb and a spliced 4.3-kb mRNA that are translated into proteins of 985 and 611 amino acids, respectively. ILTV gJ is incorporated into virions and is modified by N- and O-linked glycosylation. After cotransfection of chicken cells with genomic DNA of a pathogenic ILTV strain and transfer plasmids, gJ-negative ILTV mutants could be isolated. In vitro growth studies demonstrated that deletion of the gJ gene has only minor effects on direct cell-to-cell spread as measured by plaque size. However, progeny virus titers of ILTV-ΔgJ were significantly reduced in comparison to those of the parental virus and a gJ rescue mutant. After experimental infection of chickens the gJ rescue mutant, like wild-type ILTV, caused severe disease and considerable mortality, whereas ILTV-ΔgJ was significantly attenuated. All immunized animals were protected against subsequent challenge infection with virulent ILTV. In sera collected after immunization with the gJ-rescue mutant or with wild-type ILTV, gJ-specific antibodies were detectable by immunofluorescence on cells that had been transfected with a gJ expression plasmid. As expected, no gJ-specific antibodies were found in sera obtained from chickens immunized with ILTV-ΔgJ. Thus, gJ deletion mutants of ILTV might be usable as attenuated live-virus vaccines. Furthermore, the gJ gene might constitute a reliable marker for serological discrimination between vaccinated and field virus-infected chickens.

scholarly journals The UL47 gene of avian infectious laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens

2007 ◽  
Vol 88 (3) ◽  
pp. 732-742 ◽  
Author(s):  
Dorothee Helferich ◽  
Jutta Veits ◽  
Jens P. Teifke ◽  
Thomas C. Mettenleiter ◽  
Walter Fuchs
Keyword(s):  
Deletion Mutant ◽  
Cultured Cells ◽  
Functional Characterization ◽  
Wild Type Virus ◽  
Wild Type ◽  
Infectious Laryngotracheitis Virus ◽  
Live Virus ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus

The genome of infectious laryngotracheitis virus (ILTV) exhibits several differences from those of other avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3′-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.

scholarly journals Full Genome Sequence-Based Comparative Study of Wild-Type and Vaccine Strains of Infectious Laryngotracheitis Virus from Italy

PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0149529 ◽  
Author(s):  
Alessandra Piccirillo ◽  
Enrico Lavezzo ◽  
Giulia Niero ◽  
Ana Moreno ◽  
Paola Massi ◽  
...  
Keyword(s):  
Comparative Study ◽  
Genome Sequence ◽  
Full Genome Sequence ◽  
Full Genome ◽  
Wild Type ◽  
Infectious Laryngotracheitis Virus ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus

scholarly journals Evaluation of Recombinant Herpesvirus of Turkey Laryngotracheitis (rHVT-LT) Vaccine against Genotype VI Canadian Wild-Type Infectious Laryngotracheitis Virus (ILTV) Infection

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1425
Author(s):  
Catalina Barboza-Solis ◽  
Shahnas M. Najimudeen ◽  
Ana Perez-Contreras ◽  
Ahmed Ali ◽  
Tomy Joseph ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Clinical Signs ◽  
Wild Type ◽  
Infectious Laryngotracheitis Virus ◽  
Peripheral Blood Mononuclear ◽  
Live Attenuated Vaccine ◽  
Common Causes ◽  
Specific Pathogen ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus

In Alberta, infectious laryngotracheitis virus (ILTV) infection is endemic in backyard poultry flocks; however, outbreaks are only sporadically observed in commercial flocks. In addition to ILTV vaccine revertant strains, wild-type strains are among the most common causes of infectious laryngotracheitis (ILT). Given the surge in live attenuated vaccine-related outbreaks, the goal of this study was to assess the efficacy of a recombinant herpesvirus of turkey (rHVT-LT) vaccine against a genotype VI Canadian wild-type ILTV infection. One-day-old specific pathogen-free (SPF) White Leghorn chickens were vaccinated with the rHVT-LT vaccine or mock vaccinated. At three weeks of age, half of the vaccinated and the mock-vaccinated animals were challenged. Throughout the experiment, weights were recorded, and feather tips, cloacal and oropharyngeal swabs were collected for ILTV genome quantification. Blood was collected to isolate peripheral blood mononuclear cells (PBMC) and quantify CD4+ and CD8+ T cells. At 14 dpi, the chickens were euthanized, and respiratory tissues were collected to quantify genome loads and histological examination. Results showed that the vaccine failed to decrease the clinical signs at 6 days post-infection. However, it was able to significantly reduce ILTV shedding through the oropharyngeal route. Overall, rHVT-LT produced a partial protection against genotype VI ILTV infection.

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