PLoS ONE (Jan 2019)

Phylogeographic analysis of human influenza A and B viruses in Myanmar, 2010-2015.

  • Khin Thu Zar Htwe,
  • Clyde Dapat,
  • Yugo Shobugawa,
  • Takashi Odagiri,
  • Akinobu Hibino,
  • Hiroki Kondo,
  • Ren Yagami,
  • Takehiko Saito,
  • Nobuhiro Takemae,
  • Tsutomu Tamura,
  • Hisami Watanabe,
  • Yadanar Kyaw,
  • Nay Lin,
  • Yi Yi Myint,
  • Htay Htay Tin,
  • Win Thein,
  • Latt Latt Kyaw,
  • Pan Ei Soe,
  • Makoto Naito,
  • Hassan Zaraket,
  • Hiroshi Suzuki,
  • Takashi Abe,
  • Reiko Saito

DOI
https://doi.org/10.1371/journal.pone.0210550
Journal volume & issue
Vol. 14, no. 1
p. e0210550

Abstract

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We investigated the circulation patterns of human influenza A and B viruses in Myanmar between 2010 and 2015 by analyzing full HA genes. Upper respiratory tract specimens were collected from patients with symptoms of influenza-like illness. A total of 2,860 respiratory samples were screened by influenza rapid diagnostic test, of which 1,577 (55.1%) and 810 (28.3%) were positive for influenza A and B, respectively. Of the 1,010 specimens that were positive for virus isolation, 370 (36.6%) were A(H1N1)pdm09, 327 (32.4%) were A(H3N2), 130 (12.9%) B(Victoria), and 183 (18.1%) were B(Yamagata) viruses. Our data showed that influenza epidemics mainly occurred during the rainy season in Myanmar. Our three study sites, Yangon, Pyinmana, and Pyin Oo Lwin had similar seasonality and circulating type and subtype of influenza in a given year. Moreover, viruses circulating in Myanmar during the study period were closely related genetically to those detected in Thailand, India, and China. Phylogeographic analysis showed that A(H1N1)pdm09 viruses in Myanmar originated from Europe and migrated to other countries via Japan. Similarly, A(H3N2) viruses in Myanmar originated from Europe, and disseminated to the various countries via Australia. In addition, Myanmar plays a key role in reseeding of influenza B viruses to Southeast Asia and East Asia as well as Europe and Africa. Thus, we concluded that influenza virus in Myanmar has a strong link to neighboring Asian countries, Europe and Oceania.