Rapid and sensitive detection of infectious spleen and kidney necrosis virus by recombinase polymerase amplification combined with lateral flow dipsticks

Mandarin fish (Siniperca chuatsi) is a vital freshwater cultured species in China. Infectious spleen and kidney necrosis virus disease (ISKNVD), caused by infectious spleen and kidney necrosis virus (ISKNV), results in significant financial losses to mandarin fish farming industry. Rapid and convenient detection of ISKNV is urgent demands for diagnosis. In this study, we developed rapid, convenient and sensitive detection methods RPA (recombinase polymerase amplification) and RPA-LFD (combining RPA with lateral flow dipsticks (LFD)), targeting the conserved sequences of MCP and ORF007 genes in ISKNV. The RPA-LFD method could achieve detection within 30 min at 38 °C. Both methods had high sensitivity (102 copies/μL) and were 10 times more sensitive than that in general PCR. And they were highly specific for diagnosis of ISKNV. 24 samples of mandarin fish from farms were tested using RPA and RPA-LFD methods, both of them showed consistent results with the general PCR detection. In short, RPA and RPA-LFD provide a novel alternative for the simple, rapid and sensitive detection of ISKNV and show great potential for diagnosis of ISKNVD in the farm.