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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Endemic Poultry Viral Diseases Research » Research » Publications at this Location » Publication #419476
Research Project: Systems Biology Approaches to Develop Medical Countermeasures to Detect, Prevent, and Control Poultry Production Viral Diseases

Location: Endemic Poultry Viral Diseases Research

Title: Novel multigene molecular characterization of avian reovirus strains and associated embryonic pathogenicity

Author
item NOUR, ISLAM - Orise Fellow
item Blakey, Julia
item Alvarez Narvaez, Sonsiray
item KULKARNI, ARUN - Georgia Poultry Laboratory Network
item Read, Quentin
item Mohanty, Sujit

Submitted to: Journal of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2026
Publication Date: 5/5/2026
Citation: Nour, I., Blakey, J.R., Alvarez Narvaez, S., Kulkarni, A., Read, Q.D., Mohanty, S.K. 2026. Novel multigene molecular characterization of avian reovirus strains and associated embryonic pathogenicity. Journal of Virology. https://doi.org/10.1128/jvi.01982-25.
DOI: https://doi.org/10.1128/jvi.01982-25

Interpretive Summary: Avian Reovirus (ARV) is a serious problem for the global poultry industry, causing liver disease and arthritis in young chickens and turkeys, leading to significant financial losses. This study aimed to understand how different types of ARV affect bird embryos and whether their genetic makeup can predict their disease-causing abilities. By analyzing the complete genes of these viruses, we discovered significant differences between field strains. Our findings suggest that examining multiple parts of the virus's genes, rather than just one, provides a clearer picture of their relationships and the severity of the diseases they cause. This study also highlights the ongoing emergence of new ARV strains that are resistant to current vaccines. To effectively combat these emerging strains, it's crucial to continuously monitor ARV populations and update vaccination strategies accordingly. This will help poultry farmers control the spread of ARV and ensure a reliable and affordable food supply for consumers.

Technical Abstract: The regular monitoring of circulating avian reovirus (ARV) strains is essential for early detection of novel variants and mitigating associated clinical concerns. The molecular characterization of ARV strains is usually dependent on a single gene, sigma C, which elicits a neutralizing antibody, despite the possible contribution of other capsid proteins. This study evaluated clinical strains from the Georgia Poultry Laboratory Network for their ability to replicate and cause disease in embryos with an aim to correlate strain pathogenicity with molecular characteristics. The L3, M2, S1, and S3 genomic segments and their corresponding outer viral proteins (lambda C, µB, sigma C and sigma B respectively) were analyzed to determine if they could explain differences in strain migration patterns, host tropism, and pathogenicity. Following embryo inoculation, the study ARV strains exhibit different histopathological severities from the absence of tendon lesions in the 23-272 strain to multifocal ulceration with fibrinoheterophilic crusting in the 22-806 strain and multifocal necrotizing hepatitis in the 23-087 strain. ARV strain 23-087 showed early mortality (100%) at 2 days post-infection. The ARVs genomic migration pattern showed that the S1 segment was differentiating between virulent and non-virulent strains. Lambda C and sigma B were of the highest discriminatory power to differentiate among avian hosts. Interestingly,µB-sigma B based genotyping successfully linked the grouped strains to their virulence. The secondary structure of sigma C was the most variable among the different strains but could be differentiated according to their tendency for ß-strand configuration at the N-terminus (aa 54-145) and C-terminus (248-295), unlike sigma B that showed relatively higher conservation. The amino acid sequence variations among our strains’ sequences resulted in different antigenic epitopes mapping, which can explain the commercial vaccine strains ineffectiveness against the emerging ARV variants. To sum up, this study revealed a novel genotypic approach that can better differentiate the circulating clinical strains, define the host origin and suggest a vaccination strategies shift from focusing on the sigma C protein, to the sigma B protein, for a broader protection against various ARV strains.