title: Global alert to avian influenza virus infection: from H5N1 to H7N9.
abstract: Outbreak of a novel influenza virus is usually triggered by mutational change due to the process known as 'antigenic shift' or re-assortment process that allows animal-to-human or avian-to-human transmission. Birds are a natural reservoir for the influenza virus, and subtypes H5, H7, and H9 have all caused outbreaks of avian influenza in human populations. An especially notorious strain is the HPAI influenza virus H5N1, which has a mortality rate of approximately 60% and which has resulted in numerous hospitalizations, deaths, and significant economic loss. In March 2013, in Eastern China, there was an outbreak of the novel H7N9 influenza virus, which although less pathogenic in avian species, resulted in 131 confirmed cases and 36 deaths in humans over a two-month span. The rapid outbreak of this virus caused global concern but resulted in international cooperation to control the outbreak. Furthermore, cooperation led to valuable research-sharing including genome sequencing of the virus, the development of rapid and specific diagnosis, specimen sharing for future studies, and vaccine development. Although a H7N9 pandemic in the human population is possible due to its rapid transmissibility and extensive surveillance, the closure of the live-bird market will help mitigate the possibility of another H7N9 outbreak. In addition, further research into the source of the outbreak, pathogenicity of the virus, and the development of specific and sensitive detection assays will be essential for controlling and preparing for future H7N9 outbreaks.
authors.affiliation: Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. yong.p@chula.ac.th
authors.forename: Yong
authors.initials: Y
authors.lastname: Poovorawan
authors.forename: Sunchai
authors.initials: S
authors.lastname: Pyungporn
authors.forename: Slinporn
authors.initials: S
authors.lastname: Prachayangprecha
authors.forename: Jarika
authors.initials: J
authors.lastname: Makkoch
mesh_terms: D000818:Animals; D001717:Birds; D002681:China; D003140:Communicable Disease Control / Q000379:methods; D004196:Disease Outbreaks; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D064766:Influenza A Virus, H7N9 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology*; D016019:Survival Analysis; D015047:Zoonoses / Q000453:epidemiology* / Q000821:virology
references.citation: PLoS One. 2011 Jan 24;6(1):e14582
references.pmid: 21283678
references.citation: Virology. 1994 Nov 15;205(1):17-23
references.pmid: 7975212
references.citation: PLoS Pathog. 2009 Jan;5(1):e1000252
references.pmid: 19119420
references.citation: Cell. 1987 Aug 28;50(5):665-6
references.pmid: 3304656
references.citation: PLoS One. 2008 Aug 13;3(8):e2923
references.pmid: 18698430
references.citation: Clin Infect Dis. 2011 Jan 1;52 Suppl 1:S75-82
references.pmid: 21342903
references.citation: J Virol. 2004 May;78(9):4892-901
references.pmid: 15078970
references.citation: N Engl J Med. 2013 Jun 13;368(24):2337-9
references.pmid: 23697471
references.citation: Virus Res. 2004 Jul;103(1-2):199-203
references.pmid: 15163510
references.citation: Emerg Infect Dis. 2013 Aug;19(8):1289-92
references.pmid: 23879887
references.citation: Microbiol Rev. 1992 Mar;56(1):152-79
references.pmid: 1579108
references.citation: Proc Natl Acad Sci U S A. 2009 Mar 3;106(9):3366-71
references.pmid: 19211790
references.citation: N Engl J Med. 2005 Sep 29;353(13):1374-85
references.pmid: 16192482
references.citation: N Engl J Med. 2006 Nov 23;355(21):2174-7
references.pmid: 17124014
references.citation: MMWR Morb Mortal Wkly Rep. 2009 May 8;58(17):467-70
references.pmid: 19444150
references.citation: N Engl J Med. 2013 May 16;368(20):1888-97
references.pmid: 23577628
references.citation: Annu Rev Food Sci Technol. 2011;2:37-57
references.pmid: 22129374
references.citation: Public Health Rep. 2010 Apr;125 Suppl 3:16-26
references.pmid: 20568566
references.citation: Lancet. 1998 Feb 14;351(9101):472-7
references.pmid: 9482438
references.citation: Proc Natl Acad Sci U S A. 2004 Feb 3;101(5):1356-61
references.pmid: 14745020
references.citation: Clin Microbiol Rev. 2007 Apr;20(2):243-67
references.pmid: 17428885
references.citation: Philos Trans R Soc Lond B Biol Sci. 2001 Dec 29;356(1416):1817-28
references.pmid: 11779380
references.citation: J Mol Genet Med. 2008 Nov 27;3(1):158-66
references.pmid: 19565018
references.citation: Emerg Infect Dis. 2009 Jun;15(6):966-8
references.pmid: 19523305
references.citation: N Engl J Med. 2013 Jun 13;368(24):2277-85
references.pmid: 23697469
references.citation: N Engl J Med. 2008 Jan 17;358(3):261-73
references.pmid: 18199865
references.citation: J Vet Sci. 2009 Mar;10(1):53-60
references.pmid: 19255524
references.citation: Trends Microbiol. 1994 Feb;2(2):39-43
references.pmid: 8162439
references.citation: J Clin Microbiol. 2005 Nov;43(11):5760-7
references.pmid: 16272514
references.citation: J Virol. 1989 Nov;63(11):4603-8
references.pmid: 2795713
references.citation: Emerg Infect Dis. 2012 May;18(5):814-6
references.pmid: 22516302
references.citation: PLoS One. 2013;8(2):e56157
references.pmid: 23409145