Rapid detection of rabies virus by reverse transcription loop-mediated isothermal amplification

In this study, reverse transcription loop-mediated isothermal amplification (RT-LAMP) was established which can detect 10(3) copies of viral RNA corresponding to approximately 5 fg of RNA. RT-LAMP with the Phil primer set designed according to the nucleotide sequences obtained from a Kyoto patient who contracted rabies in the Philippines was able to amplify all 16 street viral sequences derived from the Philippines. The specificity of RT-LAMP products was easily confirmed by digestion with RsaI restriction enzyme. The reaction of RT-LAMP could be completed within 1 h and could be conducted under isothermal conditions using a conventional water bath or heat blocks, indicating that RT-LAMP is ideal for the diagnosis of rabies in developing countries. Although further study is required to establish more universal RT-LAMP primers applicable to viruses from other regions or countries, the fast, easy, simple, sensitive and specific RT-LAMP method established here might be useful for rabies diagnosis and can facilitate studies of rabies epidemiology where rabies is enzootic, particularly in developing countries.