Development of an assay for the detection and quantification of the measles virus nucleoprotein (N) gene using real-time reverse transcriptase PCR

We developed a new quantification method for the measles virus (MeV) nucleoprotein (N) gene using real-time reverse transcriptase PCR. This method allowed us to quantify 101–107 copies per reaction (corresponding to 5×10−1–5×105 copies μl−1) of the MeV N gene. We also quantified the MeV N gene from the throat swabs of 22 patients with measles as well as the MeV genotypes A, D3, D5, D9 and H1 in viral suspensions derived from MeV-infected cells. As a result, 3.9×103–5.2×106 copies ml−1 and 7.4×107–2.0×108 copies ml−1 of the MeV genomes (N gene) were detected in the throat swabs and viral suspensions, respectively. No other viruses (enteroviruses, respiratory syncytial virus, human metapneumovirus or mumps virus) were detected in the assay. The results suggest that this method is applicable to the detection and quantification of some genotypes of MeV.