Detection and genetic characterization of norovirus infections in children with acute gastroenteritis in Japan, 2007-2009.

Autor:	Chan-It W; Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan., Thongprachum A, Okitsu S, Nishimura S, Kikuta H, Baba T, Yamamoto A, Sugita K, Hashira S, Tajima T, Mizuguchi M, Ushijima H
Jazyk:	angličtina
Zdroj:	Clinical laboratory [Clin Lab] 2011; Vol. 57 (3-4), pp. 213-20.
Abstrakt:	Background: Noroviruses are a major cause of epidemic gastroenteritis in children and adults. The aim of the present study was to investigate the molecular epidemiology of norovirus gastroenteritis in Japan. Methods: A total of 954 fecal specimens collected from infants and children with acute gastroenteritis from five different regions (Tokyo, Sapporo, Saga, Osaka, and Maizuru) of Japan during 2007-2009 were identified by multiple RT-PCR and semi-nested PCR. Results: Norovirus was detected in a relatively high detection rate (26.6%; 254 of 954). Of the identified NoV, 9.5% (91 of 954) were positive by semi-nested PCR. Norovirus GII (97.3%) was more prevalent than GI (2.7%). Norovirus infections were very common in the patients aged 12-23 months (44.5%; 113 of 254). Winter month seasonality supported norovirus infection in Japan. All 7 GI sequences (100%) detected only in 2007-2008 clustered with Chiba 407 known as GI.4 genotype. Most of the norovirus GII sequences in 2007-2008 belonged to GII.4 (77.9%), followed by GII.14 (11.9%), and GII.3 and GII.6 (5.1% each). In 2008-2009, norovirus sequences were classified into eight distinct genotypes (GII.1, GII.2, GII.3, GII.4, GII.6, GII.7, GII12, and GII.14). GII.4/2006b variant was responsible for 100% among the detected GII.4 strains in both seasons. Interestingly, GII.6/GII.14 recombinant strains emerged, for the first time in Japanese children, as the second prevalent genotype (11.9%) in 2007-2008 and then dropped rapidly to 2.3% in a year after. In addition, GII.b/GII.3 and GII.4/GII.3 recombinant strains that had been described previously were also found in this study. Conclusions: This is the first report to demonstrate the co-circulation of the predominant GII.4/2006b variant and the emerging GII.6/GII.14 recombinant strains and supports the importance of norovirus as a causative agent of diarrhea in Japanese children with acute gastroenteritis.
Databáze:	MEDLINE
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