[A new method for quantitative estimation of the number of virus particles].

[In the present work virus particles of live mumps virus vaccine widely used for vaccination in Russia have been detected and visualized by atomic force microscopy. For quantitative estimation of the number of observed virus particles the special method has been proposed. The presence of protein component of the virus in vaccine was tested by ELISA and dot-blot analysis. Using quantitative real-time PCR assay the number of copies of viral RNA was estimated. The results of quantitative estimation obtained by real-time PCR corresponded with atomic force microscopy data.