Open AccessCirculation and characterization of seasonal influenza viruses in Cambodia, 2012‐2015
Author(s) -
Horwood Paul F.,
Karlsson Erik A.,
Horm Srey Viseth,
Ly Sovann,
Heng Seng,
Chin Savuth,
Darapheak Chau,
Saunders David,
Chanthap Lon,
Rith Sareth,
Y Phalla,
Chea Kim Lay,
Sar Borann,
Parry Amy,
Ieng Vanra,
Tsuyouka Reiko,
Deng YiMo,
Hurt Aeron C.,
Barr Ian G.,
Komadiomi,
Buchy Philippe,
Dussart Philippe
Publication year - 2019
Publication title -
influenza and other respiratory viruses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.743
H-Index - 57
eISSN - 1750-2659
pISSN - 1750-2640
DOI - 10.1111/irv.12647
Subject(s) - virology , antigenic drift , virus , pandemic , influenza a virus , biology , human mortality from h5n1 , medicine , covid-19 , infectious disease (medical specialty) , disease
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.