Genotypic characterization of two novel avian orthoreoviruses isolated in Iran from broilers with viral arthritis and malabsorption syndrome

Document Type : Scientific report


1 Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria

2 Graduated from School of Veterinary Medicine, Shiraz University, Shiraz, Iran

3 Graduated from Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran


Background: Avian reovirus (ARV) is a major poultry pathogen associated with arthritis, malabsorption, and enteric diseases in chickens. In recent years, emerging ARV strains have become a growing concern causing significant economic losses in broiler chickens around the world. This report focuses on the isolation of ARV from the clinical occurrence of ARV-associated diseases in commercial broiler chickens in Iran and the genotypic characterization of the selected isolates. Case description: In 2018, two distinct clinical diseases, suggestive of malabsorption syndrome (MAS) and viral arthritis, were noticed in commercial broiler chickens in the north of Iran. Laboratory investigations were carried out following necropsy, documentation of the gross lesions, and sampling of the affected tissues for histopathology and virology. Molecular diagnosis and characterization of ARV were performed targeting Sigma C (σC) gene sequences of the virus. Findings/treatment and outcome: Two variant ARV strains were isolated from tendon and gizzard of broilers with clinical viral arthritis and MAS, respectively. Phylogenetic analysis of the ARV σC gene sequences revealed that field isolates were clustered in genotypes 2 and 4 (which were distinct from previous Iranian field ARV strains) with relatively low sequence identity (59.2% and 49.1%) to the classical vaccine strains (S1133 and 1733) in genotype 1. Conclusion: This report, for the first time, represents new emerging ARV variants associated with clinical events in Iran, providing insights on the diversity of endemic ARV field isolates, and urges the need for national-wide surveillance of ARV.


Main Subjects

Ayalew, LE; Gupta, A; Fricke, J; Ahmed, KA; Popowich, S; Lockerbie, B; Tikoo, SK; Ojkic, D and Gomis, S (2017). Phenotypic, genotypic and antigenic characterization of emerging avian reoviruses isolated from clinical cases of arthritis in broilers in Saskatchewan, Canada. Sci. Rep., 7: 1-13.
Bányai, K; Dandár, E; Dorsey, KM; Mató, T and Palya, V (2011). The genomic constellation of a novel avian orthoreovirus strain associated with runting-stunting syndrome in broilers. Virus Genes. 42: 82-89.
Chen, H; Yan, M; Tang, Y and Diao, Y (2020). Sequencing and phylogenetic analysis of partial S1 genes of avian orthoreovirus isolates in Shandong province during 2015-2017. Poult. Sci., 99: 2416-2423.
Egaña-Labrin, S; Jerry, C; Roh, HJ; Da Silva, AP; Corsiglia, C; Crossley, B and Gallardo, RA (2021). Avian reoviruses of the same genotype induce different pathology in chickens. Avian Dis., 65: 529-539.
Hedayati, M; Shojadost, B and Peighambari, SM (2013). Detection of avian reoviruses causing tenosynovitis in breeder flocks in Iran by reverse transcription-polymerase chain reaction (RT-PCR) and restriction enzyme fragment length polymorphism (RFLP). Iran. J. Vet. Med., 7: 135-142.
Hedayati, M; Shoojadost, M; Peighambari, SM and Ghalyanchi Langeroudi, A (2016). Characterization of reoviruses isolated from some broiler breeder flocks in Iran. Arch. Razi Inst., 71: 227-234.
Kant, A; Balk, F; Born, L; van Roozelaar, D; Heijmans, J; Gielkens, A and ter Huurne, A (2003). Classification of Dutch and German avian reoviruses by sequencing the sigma C protein. Vet. Res., 34: 203-212.
Kumar, S; Stecher, G; Li, M; Knyaz, C and Tamura, K (2018). MEGA X: molecular evolutionary genetics analysis across computing platforms. Mol. Biol. Evol., 35: 1547-1549.
Lenz, SD; Hoerr, FJ; Ellis, AC; Toivio-Kinnucan, MA and Yu, M (1998). Gastrointestinal pathogenicity of adenoviruses and reoviruses isolated from broiler chickens in Alabama. J. Vet. Diagn. Invest., 10: 145-151.
Lu, H; Tang, Y; Dunn, PA; Wallner-Pendleton, EA; Lin, L and Knoll, EA (2015). Isolation and molecular characterization of newly emerging avian reovirus variants and novel strains in Pennsylvania, USA, 2011-2014. Sci. Rep., 5: 1-11.
Lublin, A; Goldenberg, D; Rosenbluth, E; Heller, ED and Pitcovski, J (2011). Wide-range protection against avian reovirus conferred by vaccination with representatives of four defined genotypes. Vaccine. 29: 8683-8688.
Mase, M; Gotou, M; Inoue, D; Masuda, T; Watanabe, S and Iseki, H (2021). Genetic analysis of avian reovirus isolated from chickens in Japan. Avian Dis., 65: 346-350.
Mayahi, M; Boroomand, Z; Jafari, RA; Khademian, K and Hoseini, H (2019). Molecular identification of reovirus in broiler type flocks in Golestan province, Iran. Iran. J. Vet. Res., 20: 105-111.
Meulemans, G; Boschmans, M; Van den Berg, TP and Decaesstecker, M (2001). Polymerase chain reaction combined with restriction enzyme analysis for detection and differentiation of fowl adenoviruses. Avian Pathol., 30: 655-660.
Mirbagheri, SA; Hosseini, H and Ghalyanchilangeroudi, A (2020). Molecular characterization of avian reovirus causing tenosynovitis outbreaks in broiler flocks, Iran. Avian Pathol., 49: 15-20.
Pitcovski, J and Goyal, S (2020). Avian reovirus infections. In: Swayne, DE; Boulianne, M; Logue, CM; McDougald, LR; Nair, V and Suarez, DL (Eds.), Diseases of poultry. (14th Edn.), Ames, Wiley-Blackwell. PP: 322-332.
Schachner, A; Matos, M; Grafl, B and Hess, M (2018). Fowl adenovirus-induced diseases and strategies for their control – a review on the current global situation. Avian Pathol., 47: 111-126.
Schat, KA and Sellers, HS (2008). Cell-culture methods. In: Dufour-Zavala, L; Swayne, DE; Glisson, JR; Pearson, JE; Reed, WR; Jackwood, MW and Woolcock, PR (Eds.), A laboratory manual for the isolation and identification of avianpathogens. (5th Edn.), Athens (GA): American Association of Avian Pathologists. PP: 195-203.
Sellers, HS (2017). Current limitations in control of viral arthritis and tenosynovitis caused by avian reoviruses in commercial poultry. Vet. Microbiol., 206: 152-156.
Spandidos, DA and Graham, AF (1976). Physical and chemical characterization of an avian reovirus. J. Virol., 19: 968-976.
Troxler, S; Rigomier, P; Bilic, I; Liebhart, D; Prokofieva, I; Robineau, B and Hess, M (2013). Identification of a new reovirus causing substantial losses in broiler production in France, despite routine vaccination of breeders. Vet. Rec., 172: 556.
Wickramasinghe, R; Meanger, J; Enriquez, CE and Wilcox, GE (1993). Avian reovirus proteins associated with neutralization of virus infectivity. Virology. 194: 688-696.
Yan, T; Guo, L; Jiang, X; Wang, H; Yao, Z; Zhu, S; Diao, Y and Tang, Y (2021). Discovery of a novel recombinant avian orthoreovirus in China. Vet. Microbiol., 260: 109094.
Zhang, X; Lei, X; Ma, L; Wu, J and Bao, E (2019). Genetic and pathogenic characteristics of newly emerging avian reovirus from infected chickens with clinical arthritis in China. Poult. Sci., 98: 5321-5329.