Identification of monomorphic and divergent haplotypes in the 2006-2007 norovirus GII/4 epidemic population by genomewide tracing of evolutionary history.

ABSTRACT: Our norovirus (NoV) surveillance group reported a >4-fold increase in NoV infection in Japan during the winter of 2006-2007 compared to the previous winter. Because the increase was not linked to changes in the surveillance system, we suspected the emergence of new NoV GII/4 epidemic variants. To obtain information on viral changes, we conducted full-length genomic analysis. Stool specimens from 55 acute gastroenteritis patients of various ages were collected at 11 sites in Japan between May 2006 and January 2007. Direct sequencing of long PCR products revealed 37 GII/4 genome sequences. Phylogenetic study of viral genome and partial sequences showed that the two new GII/4 variants in Europe, termed 2006a and 2006b, initially coexisted as minorities in early 2006 in Japan and that 2006b al

SUBMITTER: Motomura K 

PROVIDER: S-EPMC2573252 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature