Ultrasensitive and visual detection of pseudorabies virus based on CRISPR-Cas12b system.

Aujeszky's disease (AD) is an acute infectious disease that infects pigs and other animals, resulting in significant economic losses and posing a threat to human health. Reliable and rapid detection methods are essential for the prevention of AD. In this study, a RAA-Cas12b assay based on recombinase-aided amplification (RAA) and CRISPR-Cas12b system was established, optimized and evaluated for the rapid detection of wild-type Pseudorabies Virus (PRV). The results can not only be detected by real-time fluorescence readout, but also can be visualized by a portable blue light instrument. There was no cross-reaction with PRV Bartha-K61 strain or other swine infectious viruses. The analytical sensitivities of the real-time PRV RAA-Cas12b assay and visual PRV RAA-Cas12b assay were determined to be 15 copies/μL with 95 % confidence interval and 140 copies/μL with 95 % confidence interval, respectively. A total of 31 clinical samples were detected and compared with PRV qPCR assay to evaluate the diagnostic performance of the PRV RAA-Cas12b assay. The diagnostic coincidence rate of the two assays was 100 %. In summary, this convenient and reliable assay has great potential for rapid detection of wild type PRV in point-of-care testing (POCT).