tetano
Editor, Senior Moderator
Kamol Suwannakarn1, Thaweesak Chieochansin1, Chitima Thongmee1, Jarika Makkoch1, Kesmanee Praianantathavorn1, Apiradee Theamboonlers1, Srinand Sreevatsan2, Yong Poovorawan1*
1 Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand, 2 Departments of Veterinary Population Medicine and Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, Minnesota, United States of America
Abstract Top
Background
Annual seasonal influenza outbreaks are associated with high morbidity and mortality.
Objective
To index and document evolutionary changes among influenza A H1N1 and H3N2 viruses isolated from Thailand during 2006?2009, using complete genome sequences.
Methods
Nasopharyngeal aspirates were collected from patients diagnosed with respiratory illness in Thailand during 2006?2009. All samples were screened for Influenza A virus. A total of 13 H1N1 and 21 H3N2 were confirmed and whole genome sequenced for the evolutionary analysis using standard phylogenetic approaches.
Results
Phylogenetic analysis of HA revealed a clear diversification of seasonal from vaccine strain lineages. H3N2 seasonal clusters were closely related to the WHO recommended vaccine strains in each season. Most H1N1 isolates could be differentiated into 3 lineages. The A/Brisbane/59/2007 lineage, a vaccine strain for H1N1 since 2008, is closely related with the H1N1 subtypes circulating in 2009. HA sequences were conserved at the receptor-binding site. Amino acid variations in the antigenic site resulted in a possible N-linked glycosylation motif. Recent H3N2 isolates had higher genetic variations compared to H1N1 isolates. Most substitutions in the NP protein were clustered in the T-cell recognition domains.
Conclusion
In this study we performed evolutionary genetic analysis of influenza A viruses in Thailand between 2006?2009. Although the current vaccine strain is efficient for controlling the circulating outbreak subtypes, surveillance is necessary to provide unambiguous information on emergent viruses. In summary, the findings of this study contribute the understanding of evolution in influenza A viruses in humans and is useful for routine surveillance and vaccine strain selection.
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009717
1 Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand, 2 Departments of Veterinary Population Medicine and Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, Minnesota, United States of America
Abstract Top
Background
Annual seasonal influenza outbreaks are associated with high morbidity and mortality.
Objective
To index and document evolutionary changes among influenza A H1N1 and H3N2 viruses isolated from Thailand during 2006?2009, using complete genome sequences.
Methods
Nasopharyngeal aspirates were collected from patients diagnosed with respiratory illness in Thailand during 2006?2009. All samples were screened for Influenza A virus. A total of 13 H1N1 and 21 H3N2 were confirmed and whole genome sequenced for the evolutionary analysis using standard phylogenetic approaches.
Results
Phylogenetic analysis of HA revealed a clear diversification of seasonal from vaccine strain lineages. H3N2 seasonal clusters were closely related to the WHO recommended vaccine strains in each season. Most H1N1 isolates could be differentiated into 3 lineages. The A/Brisbane/59/2007 lineage, a vaccine strain for H1N1 since 2008, is closely related with the H1N1 subtypes circulating in 2009. HA sequences were conserved at the receptor-binding site. Amino acid variations in the antigenic site resulted in a possible N-linked glycosylation motif. Recent H3N2 isolates had higher genetic variations compared to H1N1 isolates. Most substitutions in the NP protein were clustered in the T-cell recognition domains.
Conclusion
In this study we performed evolutionary genetic analysis of influenza A viruses in Thailand between 2006?2009. Although the current vaccine strain is efficient for controlling the circulating outbreak subtypes, surveillance is necessary to provide unambiguous information on emergent viruses. In summary, the findings of this study contribute the understanding of evolution in influenza A viruses in humans and is useful for routine surveillance and vaccine strain selection.
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009717