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Basic Characteristics of Mutations
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Mutation Site
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H275Y |
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Mutation Site Sentence
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RESULTS: Oseltamivir resistance, determined by detecting the H275Y mutation in the neuraminidase (NA) gene, was observed in 2.5% (2 of 79) and 100% (77 of 77) of isolates from the 2007-2008 and 2008-2009 seasons, respectively. |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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NA |
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Standardized Encoding Gene
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NA
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Genotype/Subtype
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H1N1 |
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Viral Reference
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AB465320; AB465322; CY030230; CY030233; CY033622; CY033624; EU124136; EU124137; EU516057; EU516085; EU516083; EU516116; EU516118; EU516200; EU516257; EU516148; EU551811; EU551832; EU914903; EU914910; FJ403550; FJ445031; FJ445089; FJ654304
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Functional Impact and Mechanisms
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Disease
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Influenza A
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Immune
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- |
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Target Gene
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-
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Clinical and Epidemiological Correlations
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Clinical Information
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Y |
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Treatment
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oseltamivir |
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Location
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Japan |
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Literature Information
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PMID
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20202225
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Title
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A two-year survey of the oseltamivir-resistant influenza A(H1N1) virus in Yamagata, Japan and the clinical effectiveness of oseltamivir and zanamivir
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Author
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Matsuzaki Y,Mizuta K,Aoki Y,Suto A,Abiko C,Sanjoh K,Sugawara K,Takashita E,Itagaki T,Katsushima Y,Ujike M,Obuchi M,Odagiri T,Tashiro M
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Journal
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Virology journal
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Journal Info
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2010 Mar 5;7:53
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Abstract
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BACKGROUND: Oseltamivir is the preferred antiviral drug for influenza, but oseltamivir-resistant A(H1N1) viruses have circulated worldwide since the 2007-2008 influenza season. We aimed to determine the rate of oseltamivir resistance among A(H1N1) isolates from Yamagata, Japan, to compare the virological characteristics between isolates from the 2007-2008 and 2008-2009 seasons, and to evaluate the clinical effectiveness of oseltamivir. RESULTS: Oseltamivir resistance, determined by detecting the H275Y mutation in the neuraminidase (NA) gene, was observed in 2.5% (2 of 79) and 100% (77 of 77) of isolates from the 2007-2008 and 2008-2009 seasons, respectively. Antigenic analysis suggested that antigenically different variants of A(H1N1) viruses circulated in the 2008-2009 season. Growth testing demonstrated that the ability of the 2008-2009 isolates to replicate in MDCK cells was similar to those of the oseltamivir-susceptible isolates from the 2007-2008 season. A phylogenetic analysis revealed that two oseltamivir-resistant viruses isolated in the 2007-2008 season were closely related to other oseltamivir-susceptible viruses in Yamagata but were different from oseltamivir-resistant viruses isolated in Europe and North America in the 2007-2008 season. The oseltamivir-resistant viruses isolated in Japan in the 2008-2009 season were phylogenetically similar to oseltamivir-resistant isolates from Europe and North America during the 2007-2008 season. Furthermore, the median duration of fever after the start of oseltamivir treatment was significantly longer in oseltamivir-resistant cases (2 days; range 1-6 days) than in oseltamivir-susceptible cases (1.5 days: range 1-2 days) (P = 0.0356). CONCLUSION: Oseltamivir-resistant A(H1N1) isolates from Yamagata in the 2007-2008 season might have acquired resistance through the use of oseltamivir, and the 2008-2009 oseltamivir-resistant isolates might have been introduced into Japan and circulated throughout the country. Influenza surveillance to monitor oseltamivir-resistance would aid clinicians in determining an effective antiviral treatment strategy.
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Sequence Data
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AB521053-AB521112;AB539701-AB539710
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