TY - JOUR
T1 - Epidemiological and virological characteristics of influenza viruses circulating in Cambodia from 2009 to 2011
AU - Horm, Srey Viseth
AU - Mardy, Sek
AU - Rith, Sareth
AU - Ly, Sovann
AU - Heng, Seng
AU - Vong, Sirenda
AU - Kitsutani, Paul
AU - Ieng, Vannra
AU - Tarantola, Arnaud
AU - Ly, Sowath
AU - Sar, Borann
AU - Chea, Nora
AU - Sokhal, Buth
AU - Barr, Ian
AU - Kelso, Anne
AU - Horwood, Paul F.
AU - Timmermans, Ans
AU - Hurt, Aeron
AU - Lon, Chanthap
AU - Saunders, David
AU - Ung, Sam An
AU - Asgari, Nima
AU - Roces, Maria Concepcion
AU - Touch, Sok
AU - Komadina, Naomi
AU - Buchy, Philippe
N1 - Funding Information:
We would like to thank the following Institutions/Organizations/Project for their contribution: The World Health Organization (WHO) office in Cambodia, assisting the implementation and supporting the monitoring of influenza activity and the establishment the sentinel surveillance system for influenza-like illness (ILI); WHO Collaborating Centre for Reference and Research on Influenza, Melbourne, Australia; The Office of the Assistant Secretary for Preparedness and Response within the U.S. Department of Health and Human Services (DHHS, US); The SISEA project of French Agency for Development (AFD); Influenza Division, National Center for immunization and Respiratory Disease. Centers for Disease Control and Prevention, USA; Centers for Disease Control and Prevention, Cambodia office; National Institute of Public Health (NIPH), Phnom Penh, Cambodia; Communicable Disease Control Department, Ministry of Health, Phnom Penh, Cambodia; The Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. The Melbourne WHO Collaborating Centre for Reference and Research on Influenza is supported by the Australian Government Department of Health.
PY - 2014/10/23
Y1 - 2014/10/23
N2 - Background: The Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011.Methodology/Principal Findings: Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009-2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade.Conclusions/Significance: In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for influenza treatment and chemoprophylaxis in Cambodia, as adamantanes are no longer expected to be effective.
AB - Background: The Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011.Methodology/Principal Findings: Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009-2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade.Conclusions/Significance: In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for influenza treatment and chemoprophylaxis in Cambodia, as adamantanes are no longer expected to be effective.
UR - http://www.scopus.com/inward/record.url?scp=84908538097&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0110713
DO - 10.1371/journal.pone.0110713
M3 - Article
C2 - 25340711
AN - SCOPUS:84908538097
SN - 1932-6203
VL - 9
JO - PLoS ONE
JF - PLoS ONE
IS - 10
M1 - e110713
ER -