Standardization of the nomenclature for genetic characteristics of wild-type rubella viruses.

The main goals of the meeting--to provide guidelines for describing the major genetic groups of rubella virus and to establish uniform genetic analysis protocols--were achieved. Guidelines for describing the genotypes as an operational taxonomic group consisted of the designation of reference viruses and reference sequences for 7 genotypes of rubella viruses representing 2 clades, and designation of an additional 3 provisional genotypes. Provisional genotype status was given either because reference viruses were not yet available and/or because there was uncharacterized complexity within the genetic group. Uniform analysis protocols recommended the comparison of unknown viral sequences with the complete set of designated reference viruses, and recommended a minimum acceptable sequence window which produced phylogenetic results with high confidence values. A list of literature references about rubella virus phylogeny and molecular epidemiology is available from the WHO Internet site for this report. As additional understanding of the genetic characteristics of wild-type rubella viruses is achieved, updates to the recommended nomenclature will be made and published in the Weekly Epidemiological Record.