Abstract
Objectives: To perform genetic analysis of influenza A and B viruses in Myanmar from 2005 to 2007 and to determine the prevalence of amantadine-resistant influenza A viruses. Methods: Phylogenies of the HA and NA genes were analyzed and mutations in M2 that confer resistance to amantadine were screened. Results: Influenza in Myanmar exhibited seasonality, which coincided during the rainy season from June to August. Out of 2,618 samples, 76 influenza A and 132 influenza B viruses were isolated. Phylogenetic analysis showed that in 2005, 11 A/H1N1 isolates formed one cluster with A/Solomon Islands/3/2006 and were amantadine-sensitive strains. One A/H3N2 isolate was amantadine-resistant harboring S31N mutation in M2 and possessing S193F and D225N substitutions in HA (clade N), similar to A/Wisconsin/67/2005. No viruses were isolated in 2006 due to sample storage failure. In 2007, all 64 A/H3N2 isolates were amantadine-resistant and similar to A/Brisbane/10/2007. For influenza B, 3 Yamagata-lineage and 17 Victoria-lineage isolates were detected in 2005 and 112 Victoria-lineage viruses were isolated in 2007. All Victoria-lineage isolates were reassortants possessing NA derived from the Yamagata lineage. Conclusion: Continuous surveillance in tropical countries is important for elucidating the seasonality of influenza and determining the molecular characteristics of circulating strains.
Original language | English |
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Pages (from-to) | 310-320 |
Number of pages | 11 |
Journal | Intervirology |
Volume | 52 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2009 Nov |
Externally published | Yes |
Keywords
- Amantadine-resistant influenza A viruses
- Human influenza A and B viruses, epidemiology
- Influenza A/H1N1 viruses
- Influenza A/H3N2 Isolates
- Influenza B viruses
- Influenza surveillance, Myanmar
- Sentinel influenza surveillance sites
ASJC Scopus subject areas
- Virology
- Infectious Diseases