title: Distribution of amantadine-resistant H5N1 avian influenza variants in Asia.
abstract: We examined the distribution of genetic mutations associated with resistance to the M2 ion channel-blocking adamantane derivatives, amantadine and rimantadine, among H5N1 viruses isolated in Vietnam, Thailand, Cambodia, Indonesia, Hong Kong, and China. More than 95% of the viruses isolated in Vietnam and Thailand contained resistance mutations, but resistant mutants were less commonly isolated in Indonesia (6.3% of isolates) and China (8.9% of isolates), where human infection was recently reported. The dual mutation motif Leu26Ile-Ser31Asn (leucine-->isoleucine at aa 26 and serine-->asparagine at aa 31) was found almost exclusively in all resistant isolates from Vietnam, Thailand, and Cambodia, suggesting the biological selection of these mutations.
authors.affiliation: State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong SAR, China.
authors.forename: Chung-Lam
authors.initials: CL
authors.lastname: Cheung
authors.forename: Jane M
authors.initials: JM
authors.lastname: Rayner
authors.forename: Gavin J D
authors.initials: GJ
authors.lastname: Smith
authors.forename: Pui
authors.initials: P
authors.lastname: Wang
authors.forename: T S P
authors.initials: TS
authors.lastname: Naipospos
authors.forename: Jinxia
authors.initials: J
authors.lastname: Zhang
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
authors.forename: Robert G
authors.initials: RG
authors.lastname: Webster
authors.forename: J S Malik
authors.initials: JS
authors.lastname: Peiris
authors.forename: Yi
authors.initials: Y
authors.lastname: Guan
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
mesh_terms: D000547:Amantadine / Q000494:pharmacology*; D019943:Amino Acid Substitution; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D001208:Asia; D001717:Birds; D024882:Drug Resistance, Viral / Q000235:genetics*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000821:virology; D007251:Influenza, Human / Q000821:virology; D008826:Microbial Sensitivity Tests; D020125:Mutation, Missense; D012299:Rimantadine / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D012299:Rimantadine; D000547:Amantadine