Widespread gyrovirus co-infections in backyard chickens in Türkiye: molecular and Phylogenetic insights

INTRODUCTION: Gyroviruses are widespread small DNA viruses infecting poultry and other hosts, yet their diversity and coinfection dynamics in backyard systems remained poorly understood. MATERIALS AND METHODS: Tissue samples from 100 clinically healthy backyard chickens across five provinces in Türkiye, between 2020 and 2021, were screened using species-specific PCR assays targeting six gyroviruses. RESULTS: The Gyroviral DNA was detected in 90.0% of samples (90/100), with CAV identified in 71.0% (71/100), AGyV2 in 59.0% (59/100), GyV3 in 8.0% (8/100), GyV4 in 22.0% (22/100), GyVTu789 in 19.0% (19/100), and GyV7-SF in 18.0% (18/100) of samples. Co-infections were frequent, most notably between CAV and AGyV2, with a co occurrence rate of 25.6%. Phylogenetic analysis of partial VP1 sequences revealed that circulating strains were largely consistent with global lineages, while also displaying detectable genetic variability, particularly within GyV4. Notably, GyVTu789 and GyV7-SF were identified for the first time in chickens in Türkiye, extending their known geographic range. The high rate of co-detection highlights the concurrent circulation of multiple gyroviruses in backyard poultry populations. CONCLUSIONS: These findings provide a comprehensive overview of gyrovirus diversity and circulation dynamics, pinpointing the need for continued surveillance to better understand their epidemiology and potential impact on poultry health.