Measles Virus Genotypes

Review of the temporal and geographical distribution of measles virus genotypes 1951 – 2004

Although measles virus (MV) is serologically monotypic, the genetic characterization of wild-type viruses has identified eight clades (A – H), which have been divided into 22 genotypes and one proposed genotype. Clades B, C, D, G and H each contain multiple genotypes (B1 – 3, C1 – 2, D1 – 10, G1 – 3, H1 – 2) while clades A, E and F each contain a single genotype (A, E, F). The sequences of the vaccine strains indicate that the wild type viruses from which they were derived were all members of genotype A.
There are no known biological differences between viruses of different genotypes. Specific measles genotypes are not associated with differences in severity of disease, likelihood of developing severe sequela such as subacute sclerosing panencephalitis or inclusion body encephalitis, or variability in sensitivity of laboratory diagnosis.
Analysis of the variability in the nucleotide sequences of wild-type MVs has enabled the use of molecular epidemiologic techniques for measles surveillance. Genetic characterization of viral isolates or RT-PCR products is the only laboratory test that can differentiate between vaccine-associated cases and wild-type infection.
In 1998, the World Health Organization (WHO) recommended a standard protocol for the designation of measles genotypes. The minimum amount of sequence data required to assign a virus to a genotype are the 450 nucleotides encoding the carboxy terminus of the N protein. The entire sequence of the coding region of the H gene should be obtained from representative isolates
The purpose of this summary is to collate all available reports of MV genotypes and to standardize the published genotype nomenclature, according to the current WHO criteria, with the aim of giving a comprehensive overview of the distribution of MV genotypes in the prevaccine and postvaccine eras

Summary of distribution of MV genotypes from the prevaccine era to 2004

Refer to “Review of global temporal and geographical distribution of measles virus genotypes.pdf”
for complete referencing of data shown in figure

Data reflects publications available as of August 2005