Molecular characterization of two genotypes of mumps virus circulated in Korea during 1998–2001

Sequence analyses of the entire small hydrophobic (SH) and hemagglutinin-neuraminidase (HN) genes of mumps viruses circulated in Korea from 1998 to 2001 showed that these isolates were grouped into two genotypes, H and I. While genotype I was predominant throughout the country during this period, genotype H was found in the restricted region, 1999. The nucleotide and deduced amino acid sequences of Korean isolates showed the type-specific changes including the signature motif at positions 28–30 in the SH gene and the neutralizing epitopes in the HN gene. Particularly, Asian strains including Korean isolates and European strains differed from 2.3 to 3.8% at the nucleotide sequence level in the SH gene although they belonged to the same genotype H. Furthermore, none of Korean isolates were genetically related to the vaccine strains used in Korea. The results provide important information to understand the epidemiology of mumps infection and to facilitate the development of more efficient vaccine program in Korea.