Reverse-transcription recombinase-aided amplification assay for H7 subtype avian influenza virus

H7 subtype avian influenza virus infection is an emerging zoonosis in some Asian countries and an important avian disease worldwide. A rapid and simple test is needed to confirm infection in suspected cases during disease outbreaks. In this study, we developed a reverse-transcription recombinase-aided amplification assay for the detection of H7 subtype avian influenza virus. Assays were performed at a single temperature (39 degrees C), and the results were obtained within 20 min. The assay showed no cross-detection with Newcastle disease virus or infectious bronchitis virus, which are the other main respiratory viruses affecting birds. The analytical sensitivity was 10(2) RNA copies per reaction at a 95% probability level according to probit regression analysis, with 100% specificity. Compared with published reverse-transcription quantitative real-time polymerase chain reaction assays, the kappa value of the reverse-transcription recombinase-aided amplification assay in 342 avian clinical samples was 0.988 (p < .001). The sensitivity for avian clinical sample detection was 100% (95%CI, 90.40%-100%), and the specificity was 99.96% (95%CI, 97.83%-99.98%). These results indicated that our reverse-transcription recombinase-aided amplification assay may be a valuable tool for detecting avian influenza H7 subtype virus.