Isolation and Genotypic Characterization of New Emerging Avian Reovirus Genetic Variants in Egypt

Avian reovirus (ARV) strains cause a variety of symptoms in chickens, including viral arthritis/tenosynovitis, disease that has emerged as significant economic losses commercial chicken flocks recent years various countries, Egypt. Furthermore, ARV are frequently isolated from birds suffering malabsorption. In the actual study, seventy-five samples were collected 2021 and 2022 broiler vaccinated breeder at different farms Giza Province, Egypt, with reovirus-like such weight fluctuation arthritis/malabsorption. was screened using real-time PCR, fifteen positive detected (20%), which then subjected to embryonated egg (ECE) isolation molecular characterization (11/15 sample) partial segment sigma (σ)C gene (S1-gene). Phylogenetically, nine found belong genotypic cluster IV, 82–89% identity Israeli 2018, two V 78% nucleotide Japan 2021. No correlation between lesions genotype found. The under study had low sequence (43–55%) when compared vaccines belonging I (e.g., strain S1133). These findings imply novel genotypes representing clusters IV have recently been introduced Egyptian poultry farms. A homologous vaccine is suggested; because this variation raises possibility may not offer protection against circulating ARVs.