Circulation and characterization of seasonal influenza viruses in Cambodia, 2012‐2015

Horwood, Paul F., Karlsson, Erik A., Horm, Srey, 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, Yi-Mo, Hurt, Aeron, Barr, Ian, Komadina, Naomi, Buchy, Philippe, and Dussart, Philippe (2019) Circulation and characterization of seasonal influenza viruses in Cambodia, 2012‐2015. Influenza and other Respiratory Viruse, 13 (5). pp. 465-476.

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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.

Item ID: 58847
Item Type: Article (Research - C1)
ISSN: 1750-2659
Copyright Information: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2019 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.
Funders: World Health Organisation, Cambodia
Date Deposited: 19 Sep 2019 00:09
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320211 Infectious diseases @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 100%
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