Molecular epidemiology of mumps virus in Japan and proposal of two new genotypes

Abstract

We isolated 872 strains of mumps virus from naso-pharyngeal secretions in seven different districts of Japan from January 2000 to July 2001. Among them, 57 strains were geno-typed by nucleotide sequencing in part of the hemagglutinin-neuraminidase (HN) and small hydrophobic (SH) protein regions. Four different genotypes (B, G, K, and L) of mumps virus were co-circulating in Japan and the distribution of genotypes varied in geographically different districts. Two new clusters designated as genotypes K and L had more than 7% nucleotide variation in the SH gene. Among the 57 strains, 11 were classified as B, 35 as G, three as K, and eight as L, which was mainly isolated in Tokyo. We also examined 104 stains isolated in a clinic in Mie prefecture from 1993 to 2003. Genotype B was the indigenous strain and genotype K was introduced in 1994. Genotypes B and K co-circulated in the 1990s and were replaced by genotype G in 2000. There was no significant change in neutralizing test antibody titers against genotypes B, G, K, and L using seven post-vaccination sera with Hoshino strain (genotype B) and these four genotypes had a different antigenicity from genotype A. We should continue to watch on mumps virus molecular epidemiology.

Virological Analysis of a Regional Mumps Outbreak in the Northern Island of Japan—Mumps Virus Genotyping and Clinical Description

“…In the present outbreak, we detected MuV genotype G, which has been the predominant genotype commonly detected in recent outbreaks. The majority of MuV strains we detected were identical at the SH gene level to those previously detected in geographically and chronologically distant areas of Yamaguchi (AB105482.1) and Saitama (AB056145.1), Japan (15,16). Although not identical, 2 other MuV genotype G strains (AB105476.1-77.1) were isolated in Sapporo, Japan, which is located approximately 100 km from Fukagawa on the same island.…”

Trisaccharide containing α2,3-linked sialic acid is a receptor for mumps virus

“…Because the MuV-HN residues involved in the interaction with 3′-SL are highly conserved, the trisaccharide containing the α2,3-linked sialic acid is likely essential for all genotypes of MuV. In fact, MuV strains of the genotypes A, B, G, and L all exhibited a preference for glycans containing α2,3-linked sialic acid, although genotype A has different antigenicity than the others (23).…”

“…We also examined the binding of mumps virions of the SBL-1, Tokyo M-21 (genotype G), and Tokyo S-III-10 (genotype L) strains (23), as well as the purified HN protein of the MuV Hoshino strain (genotype B), to α2,3-and α2,6-linked sialyl glycopolymers (Neu5Acα2, 3Galβ1,4GlcNAcβ-pAP and Neu5Acα2,6Galβ1,4GlcNAcβ-pAP) (24) on microplates. All MuV particles examined bound to α2,3-linked sialyl glycopolymers, but not to α2,6-linked sialyl glycopolymers (Fig.…”

Function of Small Hydrophobic Proteins of Paramyxovirus

“…Due to the variability among different strains of MuV SH, the SH gene has been used as a marker to categorize mumps virus isolates (45). At present, there are 12 different mumps virus groups (A to L) based on their SH gene sequences (20,21,55).…”