Detection of avian reoviruses causing tenosynovitis in breeder flocks of Iran by reverse transcription-polymerase chain reaction (RT-PCR) and restriction enzyme fragment length polymorphism (RFLP)

Avian reoviruses (ARVs) are members of the Orthoreovirus genus; one of the 12 genera of the Reoviridae family. The ARVs are the cause of some important diseases in poultry such as reovirus-induced arthritis، tenosynovitis، chronic respiratory disease، and mal-absorption syndrome. In this study، the presence of ARVs in the Iranian breeder flocks was investigated through reverse transcriptionpolymerase chain reaction (RT-PCR) and restriction enzyme fragment length polymorphism (RFLP). A total of 800 fecal swab samples were initially collected from breeder flocks (older than 45 weeks of age). They were then sent to the laboratory in containers with PBS، and after that they were pooled and finally to 120 samples were obtained. The total RNA extracted from the pooled fecal samples were used to amplify the selected parts of the S1 (1023 bp) and S4 (437 bp) genes from the ARV field isolates using RT-PCR. The positive RT-PCR amplified products were further analyzed by RFLP using five restriction enzymes. Based on the findings، 5 samples were positive with the S1 primer and 6 samples were with the S4 one. The patterns observed after the digestion of PCR products revealed that the isolates of this study were identical to both the S1133 vaccine and standard strains. The findings suggested that the RT-PCR/RFLP analysis might be considered as a simple and rapid approach for the differentiation of ARVisolates. This study was the first molecular detection of the ARVs presence in the Iranian breeder flocks using the RTPCR amplification of the S1 and S4 genes and RFLP analysis.