A CRISPR-based nucleic acid detection method for severe fever with thrombocytopenia syndrome virus

Fever with thrombocytopenia syndrome virus (SFTS) is a tick-borne infection now known to spread among humans as an aerosol, which has resulted in several outbreaks across Asia over the past decade. As mortality is substantial, it is vital to establish a rapid, on-site nucleic acid detection method for diagnosis. Here we describe such a method for SFTSV (Dabie bandavirus) based on CRISPR-Cas13a.

Specific recombinase-aided amplification (RAA) primers and CRISPR (cr)RNA nucleic acid detection targets were designed and synthesized for the conserved sequence of the SFTSV genome, and fluorescent CRISPR detection was used to screen for high-sensitivity crRNAs. Colloidal immunochromatography test paper was used to read CRISPR detection results. Sensitivity and specificity were evaluated by running tests on gradient dilutions of SFTSV nucleic acid and the nucleic acids of other pathogens with similar transmission routes or clinical manifestations.

One crRNA with high detection sensitivity was screened out of 5 crRNAs with conserved sequences from the SFTSV genome. This CRISPR nucleic acid-based detection method was able to detect a single crRNA copy per microliter but not the nucleic acids of similar pathogens.

This CRISPR test strip detection method permits rapid, sensitive, and specific diagnosis of SFTS without the need for advanced nucleic acid detection equipment, thus allowing for on-site application.