1. Monitoring and characterization of oseltamivir-resistant pandemic (H1N1) 2009 virus, Japan, 2009-2010.
- Author
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Ujike M, Ejima M, Anraku A, Shimabukuro K, Obuchi M, Kishida N, Hong X, Takashita E, Fujisaki S, Yamashita K, Horikawa H, Kato Y, Oguchi A, Fujita N, Tashiro M, and Odagiri T
- Subjects
- Adolescent, Adult, Antiviral Agents therapeutic use, Child, Child, Preschool, Female, Hemagglutination Inhibition Tests, Humans, Infant, Infant, Newborn, Influenza A Virus, H1N1 Subtype classification, Influenza A Virus, H1N1 Subtype genetics, Influenza, Human drug therapy, Influenza, Human epidemiology, Influenza, Human transmission, Japan epidemiology, Male, Microbial Sensitivity Tests, Middle Aged, Mutation, Neuraminidase genetics, Oseltamivir therapeutic use, Sequence Analysis, DNA, Young Adult, Antiviral Agents pharmacology, Drug Resistance, Viral genetics, Influenza A Virus, H1N1 Subtype drug effects, Influenza, Human virology, Oseltamivir pharmacology, Pandemics
- Abstract
To monitor and characterize oseltamivir-resistant (OR) pandemic (H1N1) 2009 virus with the H275Y mutation, we analyzed 4,307 clinical specimens from Japan by neuraminidase (NA) sequencing or inhibition assay; 61 OR pandemic (H1N1) 2009 viruses were detected. NA inhibition assay and M2 sequencing indicated that OR pandemic (H1N1) 2009 virus was resistant to M2 inhibitors, but sensitive to zanamivir. Full-genome sequencing showed OR and oseltamivir-sensitive (OS) viruses had high sequence similarity, indicating that domestic OR virus was derived from OS pandemic (H1N1) 2009 virus. Hemagglutination inhibition test demonstrated that OR and OS pandemic (H1N1) 2009 viruses were antigenically similar to the A/California/7/2009 vaccine strain. Of 61 case-patients with OR viruses, 45 received oseltamivir as treatment, and 10 received it as prophylaxis, which suggests that most cases emerged sporadically from OS pandemic (H1N1) 2009, due to selective pressure. No evidence of sustained spread of OR pandemic (H1N1) 2009 was found in Japan; however, 2 suspected incidents of human-to-human transmission were reported.
- Published
- 2011
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