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Influenza Other Respir Viruses. 2019 Jun 28. doi: 10.1111/irv.12647. [Epub ahead of print]
Circulation and characterization of seasonal influenza viruses in Cambodia, 2012-2015.
Horwood PF1,2, Karlsson EA1, Horm SV1, Ly S3, Heng S3, Chin S4, Darapheak C4, Saunders D5, Chanthap L5, Rith S1, Y P1, Chea KL1, Sar B6, Parry A7, Ieng V7, Tsuyouka R7, Deng YM8, Hurt AC8, Barr IG8, Komadina N8,9, Buchy P1,10, Dussart P1.
Author information
Abstract
BACKGROUND:
Influenza virus circulation is monitored through the Cambodian influenza-like illness (ILI) sentinel surveillance system and isolates are characterized by the National Influenza Centre (NIC). Seasonal influenza circulation has previously been characterized by year-round activity and a peak during the rainy season (June-November).
OBJECTIVES:
We documented the circulation of seasonal influenza in Cambodia for 2012-2015 and investigated genetic, antigenic, and antiviral resistance characteristics of influenza isolates.
PATIENTS/METHODS:
Respiratory samples were collected from patients presenting with influenza-like illness (ILI) at 11 hospitals throughout Cambodia. First-line screening was conducted by the National Institute of Public Health and the Armed Forces Research Institute of Medical Sciences. Confirmation of testing and genetic, antigenic and antiviral resistance characterization was conducted by Institute Pasteur in Cambodia, the NIC. Additional virus characterization was conducted by the WHO Collaborating Centre for Reference and Research on Influenza (Melbourne, Australia).
RESULTS:
Between 2012 and 2015, 1,238 influenza-positive samples were submitted to the NIC. Influenza A(H3N2) (55.3%) was the dominant subtype, followed by influenza B (30.9%; predominantly B/Yamagata-lineage) and A(H1N1)pdm09 (13.9%). Circulation of influenza viruses began earlier in 2014 and 2015 than previously described, coincident with the emergence of A(H3N2) clades 3C.2a and 3C.3a, respectively. There was high diversity in the antigenicity of A(H3N2) viruses, and to a smaller extent influenza B viruses, during this period, with some mismatches with the northern and southern hemisphere vaccine formulations. All isolates tested were susceptible to the influenza antiviral drugs oseltamivir and zanamivir.
CONCLUSIONS:
Seasonal and year-round co-circulation of multiple influenza types/subtypes were detected in Cambodia during 2012-2015.
? 2019 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.
KEYWORDS:
A(H1N1)pdm09; A(H3N2); Cambodia; influenza A virus; influenza B virus; surveillance
PMID: 31251478 DOI: 10.1111/irv.12647
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Circulation and characterization of seasonal influenza viruses in Cambodia, 2012-2015.
Horwood PF1,2, Karlsson EA1, Horm SV1, Ly S3, Heng S3, Chin S4, Darapheak C4, Saunders D5, Chanthap L5, Rith S1, Y P1, Chea KL1, Sar B6, Parry A7, Ieng V7, Tsuyouka R7, Deng YM8, Hurt AC8, Barr IG8, Komadina N8,9, Buchy P1,10, Dussart P1.
Author information
Abstract
BACKGROUND:
Influenza virus circulation is monitored through the Cambodian influenza-like illness (ILI) sentinel surveillance system and isolates are characterized by the National Influenza Centre (NIC). Seasonal influenza circulation has previously been characterized by year-round activity and a peak during the rainy season (June-November).
OBJECTIVES:
We documented the circulation of seasonal influenza in Cambodia for 2012-2015 and investigated genetic, antigenic, and antiviral resistance characteristics of influenza isolates.
PATIENTS/METHODS:
Respiratory samples were collected from patients presenting with influenza-like illness (ILI) at 11 hospitals throughout Cambodia. First-line screening was conducted by the National Institute of Public Health and the Armed Forces Research Institute of Medical Sciences. Confirmation of testing and genetic, antigenic and antiviral resistance characterization was conducted by Institute Pasteur in Cambodia, the NIC. Additional virus characterization was conducted by the WHO Collaborating Centre for Reference and Research on Influenza (Melbourne, Australia).
RESULTS:
Between 2012 and 2015, 1,238 influenza-positive samples were submitted to the NIC. Influenza A(H3N2) (55.3%) was the dominant subtype, followed by influenza B (30.9%; predominantly B/Yamagata-lineage) and A(H1N1)pdm09 (13.9%). Circulation of influenza viruses began earlier in 2014 and 2015 than previously described, coincident with the emergence of A(H3N2) clades 3C.2a and 3C.3a, respectively. There was high diversity in the antigenicity of A(H3N2) viruses, and to a smaller extent influenza B viruses, during this period, with some mismatches with the northern and southern hemisphere vaccine formulations. All isolates tested were susceptible to the influenza antiviral drugs oseltamivir and zanamivir.
CONCLUSIONS:
Seasonal and year-round co-circulation of multiple influenza types/subtypes were detected in Cambodia during 2012-2015.
? 2019 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.
KEYWORDS:
A(H1N1)pdm09; A(H3N2); Cambodia; influenza A virus; influenza B virus; surveillance
PMID: 31251478 DOI: 10.1111/irv.12647
Free full text