Molecular characterization of turkey enteric reovirus S3 gene

Abstract

The molecular diversity in S3 gene sequences of turkey reovirus (TRV) was determined in poult enteritis syndrome (PES)-affected and apparently healthy turkey poults. Twenty-nine TRV-positive samples (15 from PESaffected flocks and 14 from apparently healthy flocks) were tested using self-designed primers for the S3 gene. Phylogenetic analysis revealed that the TRV S3 sequences of this study clustered in clade III and formed two different groups in this clade. The avian reoviruses from duck and goose formed clade I and those from chickens formed clade II. The clade III TRV sequences had a nucleotide percent identity of 88.9 to 100% among themselves but only of 59.5 to 63.5% and 69.2 to 72.6% with clades I and II, respectively. More amino acid substitutions were present in TRVs from PES-affected flocks than in those from apparently healthy flocks using ATCC VR-818 (AY444912) as a benchmark. All TRVs of this study showed substitutions at positions 244 and 285. The impact of these changes on the virulence of the virus, if any, needs to be studied.

Phylogenetic analysis, genomic diversity and classification of M class gene segments of turkey reoviruses

“…Further genetic studies on TRVs from different geographical areas are required to confirm or refute this observation. Variations at nucleotide and amino acid levels in S segment of turkey reoviruses in comparison to reoviruses of chicken, duck and goose origin have earlier been reported (Day et al, 2007;Jindal et al, 2010Jindal et al, , 2014Mor et al, 2014a). In all M class segments, the variations within the TRV sequences suggested that synonymous changes were higher than non-synonymous changes, which is in agreement with previous M class studies in CRVs, DRVs and GRVs (Noad et al, 2006;Su et al, 2006;Wang et al, 2013;Zhang et al, 2007).…”

“…TERVs have been isolated from apparently healthy and enteritis-affected turkeys for years (Pantin-Jackwood et al, 2008;Jindal et al, 2010Jindal et al, , 2014 but, until recently, there have been no reports on reovirus-associated lameness and arthritis in turkeys after it was first reported in the 1980s (Levisohn et al, 1980;Al Afaleq and Jones, 1989). After a hiatus of >20 years, the problem of turkey arthritis reemerged in the upper Midwest area initially and then was reported from several other US states in both commercial and breeder turkey flocks.…”

“…The ARVs of turkeys (turkey reoviruses or TRVs) have been isolated not only from apparently healthy poults but also from cases of poult enteritis complex (PEC), poult enteritis syndrome (PES), and light turkey syndrome (LTS) (Pantin-Jackwood et al, 2008;Mor et al, 2013a;Jindal et al, 2010Jindal et al, , 2014. In 1980s, TRVs were isolated from arthritic joints of turkeys (Levisohn et al, 1980;Page et al, 1982;Al Afaleq and Jones, 1990).…”

A Snapshot on the Genomic Epidemiology of Turkey Reovirus Infections, Hungary

“…Even with the advancement of rapid genome amplification and sequencing methods, roughly a dozen TRV whole-genome sequences were available at the time when we started to prepare this paper. Studies published so far have indicated that turkey reoviruses separated from waterfowl origin orthoreoviruses, and they constitute in most genes distinct phylogenetic clades separated even from chicken origin orthoreoviruses [14,27,28,36,37]. Of interest, shared genes were observed when comparing turkey-origin reovirus strains with partridge-and pheasant-origin orthoreoviruses [10,38].…”

Genome Sequences of Three Turkey Orthoreovirus Strains Isolated in Hungary

“…ARVs and reovirus associated diseases have been detected worldwide since the middle of the last century in commercial poultry and also in different wild-living or captive-bred bird species ( 2 – 9 ). Turkey reovirus (TRV) infections are usually associated with different disease manifestations including arthritis, tenosynovitis, myocarditis, and/or enteric symptoms ( 6 , 10 – 13 ).…”