SUMMARY
Avian reovirus (ARV) antigenic and genetic variants pose a significant threat to the poultry industry, causing arthritis and tenosynovitis in broiler chickens and resulting in substantial economic losses and welfare issues. Continuous surveillance efforts are important to detect circulating ARV genetic and antigenic variants to update autogenous vaccines needing periodic reformulation to represent field challenge viruses. This study aimed to isolate and genotype ARV genetic variants between 2020 and 2022 from a single broiler chicken company. Clinical and surveillance data from previous years (2017–2019) were also included in this study to analyze the trends of ARV cases from the same company. Out of 40 isolates, between 2020 and 2022, 35 reoviruses were successfully amplified and sequenced. These genetic variants were classified into six of the seven described genotypic clusters, with GC2 (31.43%) and GC5 (25.71%) emerging as the predominant clusters. These results indicate a shift from our previous findings where GC1 and GC6 were the most prevalent. On average, GC1 demonstrated 75% homology compared to the reference strain S1133, and other genotypic clusters exhibited reduced amino acid identity ranging from 54% to 45%. The results of this study suggest a potential impact of autogenous vaccines in reducing ARV cases and reveal a decrease in viral load over the years.