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.
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.
Authors: Tommy Tsan-Yuk Lam; Huachen Zhu; David K Smith; Yi Guan; Edward C Holmes; Oliver G Pybus Journal: J Gen Virol Date: 2012-01-13 Impact factor: 3.891
Authors: Glicélia Cruz Aragão; Joana D'Arc Pereira Mascarenhas; Jane Haruko Lima Kaiano; Maria Silvia Sousa de Lucena; Jones Anderson Monteiro Siqueira; Túlio Machado Fumian; Juliana das Mercês Hernandez; Consuelo Silva de Oliveira; Darleise de Souza Oliveira; Eliete da Cunha Araújo; Luana da Silva Soares; Alexandre Costa Linhares; Yvone Benchimol Gabbay Journal: PLoS One Date: 2013-02-15 Impact factor: 3.240
Authors: M C Medici; F Tummolo; V Martella; C Chezzi; M C Arcangeletti; F De Conto; A Calderaro Journal: Epidemiol Infect Date: 2014-01-20 Impact factor: 4.434