Integration of RPA and CRISPR-Cas13a collateral activity for one-step detection of DHAV-3: A biological...

Duck hepatitis A virus type 3 (DHAV-3), which is families of the Picornaviridae, poses severe threats to waterfowl industries due to rapid antigenic evolution and limitations in conventional diagnostics. Herein, we engineered a CRISPR-Cas13a-mediated RNA detection system by leveraging the intrinsic HEPN domain-dependent collateral cleavage activity of Cas13a, synergistically integrated with recombinase polymerase amplification (RPA) to target DHAV-3 RNA. This biological macromolecule-driven platform achieved ultrasensitive detection (1 copies/microL) within 35 min through sequence-specific crRNA guidance and Cas13a-triggered fluorescent/lateral flow signal amplification. Rigorous validation against four avian pathogens (ARV, H9N2 AIV, TMUV, AstV) confirmed 100 % specificity, highlighting the precise macromolecular interactions between Cas13a and target RNA. Clinical evaluation of 30 field samples demonstrated complete concordance with RT-qPCR. By harnessing the programmable functionality of Cas13a and the thermostable enzymes in RPA, this study provides a novel paradigm for RNA-guided biological macromolecule applications in point-of-care diagnostics, bridging molecular mechanisms with agricultural biosecurity needs.