Key result
Emerging Canadian avian reovirus strains show broad genetic diversity and evade commercial vaccine neutralization.
Why the study?
Emerging strains of pathogenic arthrogenic avian reovirus have become a challenge to the chicken industry in USA and Canada causing significant economic impact, but their genetic and antigenic characteristics were not well described.
Observational (n=1,980)
Emerging avian reovirus strains causing arthritis in Canadian broilers show significant genetic and antigenic diversity and are not neutralized by current commercial vaccines.
May signal inadequate protection from existing poultry vaccines; leaves open needs for expanded surveillance and updated formulations.
In recent years, emerging strains of pathogenic arthrogenic avian reovirus (ARV) have become a challenge to the chicken industry across USA and Canada causing significant economic impact. In this study, we characterized emerging variant ARV strains and examined their genetic and antigenic relationship with reference strains. We isolated 37 emerging variant ARV strains from tendons of broiler chickens with clinical cases of arthritis/tenosynovitis at commercial farms in Saskatchewan, Canada. Viral characterization using immunocytochemistry, gold-immunolabeling and electron microscopy revealed distinct features characteristic of ARV. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the viral Sigma C gene revealed genetic heterogeneity between the field isolates. On phylogenetic analyses, the Sigma C amino acid sequences of the isolates were clustered into four distinct genotypic groups. These ARV field strains were genetically diverse and quite distant from the vaccine and vaccine related field strains. Antibodies produced against a commercial Reo 2177®vaccine did not neutralize these variants. Moreover, structure based analysis of the Sigma C protein revealed significant antigenic variability between the cluster groups and the vaccine strains. To the best of our knowledge, this is the first report on the genetic, phenotypic and antigenic characterization of emerging ARVs in Canada.
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Ayalew et al. (2017) conducted an observational in Avian reovirus-associated arthritis/tenosynovitis (n=1,980). Emerging avian reovirus (ARV) variant strains vs. Commercial ARV vaccine strains was evaluated on Genetic, phenotypic and antigenic characterization of ARV isolates. Emerging avian reovirus strains from broiler chickens in Canada were genetically diverse, clustered into four genotypic groups, and evaded neutralization by antibodies from a commercial vaccine.
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