Improved RT-PCR for diagnosis and epidemiological surveillance of rubella.

A reverse transcription nested polymerase chain reaction (RT-PCR) assay was developed and evaluated for detection of rubella virus (RV) RNA directly from clinical specimens using primers that amplified 592 nucleotides, of a variable region within the E1 gene. RV RNA was detected in pre- and post-natal congenital rubella samples and samples from patients with acute rubella, which suggests that it is a reliable technique for rubella diagnosis and surveillance. The sensitivity of the PCR was found to be equivalent to that of previously published assays, which amplify smaller regions of the E1 gene. This improved RT-PCR is much more specific for detection of the rubella genome compared to our previous PCR, where some primers were complementary to the human genome. The larger size of the PCR amplicon was also useful for molecular genotyping of virus strains.