An optimized visual loop mediated isothermal amplification assay for efficient detection of minute virus of mice with hydroxynaphthol blue dye.

Minute virus of mice (MVM) is one of the most prevalent infectious agents in laboratory mouse colonies. In this study, we optimized a loop-mediated isothermal amplification (LAMP) assay using hydroxynaphthol blue (HNB) for rapid and visual detection of MVM. The reaction, which entailed addition of HNB dye prior to amplification, was performed in one step in a single tube at 62 °C for 45 min. The limit of detection of the assay was 104 copies, which was 100-fold lower than that of conventional PCR. The assay specifically amplified MVM DNA and did not cross-react with other viruses. To validate the established LAMP system, we applied it 287 samples and detected 19 positives. In conclusion, LAMP with HNB is a sensitive, and simple assay for rapid detection of MVM infections in laboratory animals, thus offers a platform for quality monitoring.