Development of a rapid and portable detection method for canine distemper virus based on CRISPR-Cas13a

Canine distemper virus (CDV) is a pathogenic microorganism that severely affects the respiratory, digestive, and nervous systems, causing multi-systemic symptoms. It infects nearly all terrestrial carnivores worldwide, particularly the Canidae and Mustelidae families, posing a serious threat to global socio-economic and public health security. Given the importance of etiological treatment and early diagnosis, developing novel detection methods with improved accuracy, rapidity, and user-friendliness is necessary for effective prevention and control of CDV infection. In this study, we established a novel testing method using recombinase-aid amplification (RAA) coupled with CRISPR-Cas13a and optimized the working concentration of CRISPR RNA (crRNA) and Cas13a for the lateral flow detection (LFD) of CDV. The RAA-CRISPR-Cas13a-LFD for CDV did not cross-react against other prevalent canine pathogens and the sensitivity can detect as little as 10² copies/μL of CDV cDNA plasmids. Additionally, combined with HUDSON this RAA-CRISPR-Cas13a-LFD method could be used to detect clinical samples within 1.5 h, with performance comparable to that of RT-PCR. The results for the RAA-CRISPR-Cas13a detection could be visualized using either fluorescence or lateral flow strips for in field-deployable viral diagnosis. Overall, our developed method showed good potential in point-of-care testing (POCT) to control and reduce the losses by CDV infection.