Rapid detection of by recombinase-aided amplification combined with the CRISPR/Cas12a system.

() is one of the primary agents involved in porcine respiratory disease complex, and circulates in the swine industry worldwide. The prevention and control of is complicated. Thus, a recombinase-aided amplification (RAA) assay coupled with the clustered regularly-interspaced short palindromic repeats (CRISPR)/Cas12a system was established for the detection of . The most suitable primer pairs and CRISPR RNA (crRNA) were screened and selected for the RAA-CRISPR/Cas12a detection system. We have achieved a detection limit of 1 copy/µL and 5 copies/µL per reaction for the RAA-CRISPR/Cas12a-fluorescence assay and RAA-CRISPR/Cas12a-lateral flow assay (LFA), respectively. Furthermore, the RAA-CRISPR/Cas12a system displayed no cross-reactivity with other respiratory pathogens. The performance of the RAA-CRISPR/Cas12a system was compared with PCR as recommended by the Chinese national standard (GB/T 35909-2018) and qPCR as recommended by the Chinese entry-exit inspection and quarantine industry standard (SN/T4104-2015) for clinical samples, and good consistency with these methods was observed. Above all, the methods shed a light on the convenient, portable, visual, highly sensitive and specific detection of , demonstrating a great application potential for on-site monitoring of in the field.