Development of a loop-mediated isothermal amplification assay for the rapid detection of Alongshan virus

Alongshan virus (ALSV) is a recently discovered tick-borne zoonotic virus. Currently, there is no rapid and accurate clinical method for ALSV detection. This study aimed to develop a loop-mediated isothermal amplification (LAMP) assay for precise ALSV infection detection. Specific primers were designed based on the S1 segment of the ALSV NE-TH4 strain's genome (GenBank accession no. ON408067.1). The reaction time, temperature and concentration of the neutral red staining solution in the LAMP assay were optimized. Thorough evaluations of specificity, sensitivity and repeatability led to the development of a visually interpretable LAMP assay. The optimal amplification time was 50 min. The minimum detection limit for cDNA was as low as 0.005 pg μl^-1, and sensitivity for standards was 1.68×10³ copies per μl, surpassing that of PCR and real-time PCR. No cross-reactivity was observed with Jingmen tick virus, Bole tick virus 4 and Beiji nairovirus. These results indicate that the LAMP assay is more sensitive and accurate than PCR and real-time PCR. The developed LAMP assay allows for on-site detection, reduces testing costs and provides rapid and accurate results. Thus, it lays a solid foundation for the prevention and control of emerging tick-borne ALSV.