Volume 85, Issue 5
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



During the early months of 2009, a novel influenza A/H1N1 virus (pH1N1) emerged in Mexico and quickly spread across the globe. In October 2009, a 23-year-old male residing in central Cambodia was diagnosed with pH1N1. Subsequently, a cluster of four influenza-like illness cases developed involving three children who resided in his home and the children's school teacher. Base composition analysis of internal genes using reverse transcriptase polymerase chain reaction and electrospray ionization mass spectrometry revealed that specimens from two of the secondary victims were coinfected with influenza A/H3N2 and pH1N1. Phylogenetic analysis of the hemagglutinin genes from these isolated viruses showed that they were closely related to existing pH1N1 and A/H3N2 viruses circulating in the region. Genetic recombination was not evident within plaque-purified viral isolates on full genome sequencing. This incident confirms dual influenza virus infections and highlights the risk of zoonotic and seasonal influenza viruses to coinfect and possibly, reassort where they cocirculate.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...



  1. Simonsen L, , 1999. The global impact of influenza on morbidity and mortality. Vaccine 17 (Suppl 1): S3S10.[Crossref] [Google Scholar]
  2. Webby RJ, Woolcock PR, Krauss SL, Webster RG, , 2002. Reassortment and interspecies transmission of North American H6N2 influenza viruses. Virology 295: 4453.[Crossref] [Google Scholar]
  3. Zhou NN, Senne DA, Landgraf JS, Swenson SL, Erickson G, Rossow K, Liu L, Yoon K, Krauss S, Webster RG, , 1999. Genetic reassortment of avian, swine, and human influenza A viruses in American pigs. J Virol 73: 88518856. [Google Scholar]
  4. Obenauer JC, Denson J, Mehta PK, Su X, Mukatira S, Finkelstein DB, Xu X, Wang J, Ma J, Fan Y, Rakestraw KM, Webster RG, Hoffmann E, Krauss S, Zheng J, Zhang Z, Naeve CW, , 2006. Large-scale sequence analysis of avian influenza isolates. Science 311: 15761580.[Crossref] [Google Scholar]
  5. World Health Organization, 2009. New influenza A (H1N1) virus: WHO guidance on public health measures, 11 June 2009. Wkly Epidemiol Rec 84: 261264. [Google Scholar]
  6. Blair PJ, Wierzba TF, Touch S, Vonthanak S, Xu X, Garten RJ, Okomo-Adhiambo MA, Klimov AI, Kasper MR, Putnam SD, , 2010. Influenza epidemiology and characterization of influenza viruses in patients seeking treatment for acute fever in Cambodia. Epidemiol Infect 138: 199209.[Crossref] [Google Scholar]
  7. Mardy S, Ly S, Heng S, Vong S, Huch C, Nora C, Asgari N, Miller M, Bergeri I, Rehmet S, Veasna D, Zhou W, Kasai T, Touch S, Buchy P, , 2009. Influenza activity in Cambodia during 2006–2008. BMC Infect Dis 9: 168.[Crossref] [Google Scholar]
  8. Dawood FS, Jain S, Finelli L, Shaw MW, Lindstrom S, Garten RJ, Gubareva LV, Xu X, Bridges CB, Uyeki TM, , 2009. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med 360: 26052615.[Crossref] [Google Scholar]
  9. Sampath R, Russell KL, Massire C, Eshoo MW, Harpin V, Blyn LB, Melton R, Ivy C, Pennella T, Li F, Levene H, Hall TA, Libby B, Fan N, Walcott DJ, Ranken R, Pear M, Schink A, Gutierrez J, Drader J, Moore D, Metzgar D, Addington L, Rothman R, Gaydos CA, Yang S, St George K, Fuschino ME, Dean AB, Stallknecht DE, Goekjian G, Yingst S, Monteville M, Saad MD, Whitehouse CA, Baldwin C, Rudnick KH, Hofstadler SA, Lemon SM, Ecker DJ, , 2007. Global surveillance of emerging influenza virus genotypes by mass spectrometry. PLoS One 2: e489.[Crossref] [Google Scholar]
  10. Ghedin E, Sengamalay NA, Shumway M, Zaborsky J, Feldblyum T, Subbu V, Spiro DJ, Sitz J, Koo H, Bolotov P, Dernovoy D, Tatusova T, Bao Y, St George K, Taylor J, Lipman DJ, Fraser CM, Taubenberger JK, Salzberg SL, , 2005. Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution. Nature 437: 11621166.[Crossref] [Google Scholar]
  11. Brown EG, Liu H, Kit LC, Baird S, Nesrallah M, , 2001. Pattern of mutation in the genome of influenza A virus on adaptation to increased virulence in the mouse lung: identification of functional themes. Proc Natl Acad Sci USA 98: 68836888.[Crossref] [Google Scholar]
  12. Chidlow G, Harnett G, Williams S, Levy A, Speers D, Smith DW, , 2010. Duplex real-time reverse transcriptase PCR assays for rapid detection and identification of pandemic (H1N1) 2009 and seasonal influenza A/H1, A/H3, and B viruses. J Clin Microbiol 48: 862866.[Crossref] [Google Scholar]
  13. Lee N, Chan PK, Lam WY, Szeto CC, Hui DS, , 2010. Co-infection with pandemic H1N1 and seasonal H3N2 influenza viruses. Ann Intern Med 152: 618619.[Crossref] [Google Scholar]
  14. Liu W, Li ZD, Tang F, Wei MT, Tong YG, Zhang L, Xin ZT, Ma MJ, Zhang XA, Liu LJ, Zhan L, He C, Yang H, Boucher CA, Richardus JH, Cao WC, , 2010. Mixed infections of pandemic H1N1 and seasonal H3N2 viruses in 1 outbreak. Clin Infect Dis 50: 13591365.[Crossref] [Google Scholar]
  15. Peacey M, Hall RJ, Sonnberg S, Ducatez M, Paine S, Nicol M, Ralston JC, Bandaranayake D, Hope V, Webby RJ, Huang S, , 2010. Pandemic (H1N1) 2009 and seasonal influenza A (H1N1) co-infection, New Zealand, 2009. Emerg Infect Dis 16: 16181620.[Crossref] [Google Scholar]
  16. Webster RG, Laver WG, , 1972. Studies on the origin of pandemic influenza. I. Antigenic analysis of A 2 influenza viruses isolated before and after the appearance of Hong Kong influenza using antisera to the isolated hemagglutinin subunits. Virology 48: 433444.[Crossref] [Google Scholar]
  17. Scholtissek C, Rohde W, Von Hoyningen V, Rott R, , 1978. On the origin of the human influenza virus subtypes H2N2 and H3N2. Virology 87: 1320.[Crossref] [Google Scholar]
  18. Garten RJ, Davis CT, Russell CA, Shu B, Lindstrom S, Balish A, Sessions WM, Xu X, Skepner E, Deyde V, Okomo-Adhiambo M, Gubareva L, Barnes J, Smith CB, Emery SL, Hillman MJ, Rivailler P, Smagala J, de Graaf M, Burke DF, Fouchier RA, Pappas C, Alpuche-Aranda CM, Lopez-Gatell H, Olivera H, Lopez I, Myers CA, Faix D, Blair PJ, Yu C, Keene KM, Dotson PD Jr, Boxrud D, Sambol AR, Abid SH, St George K, Bannerman T, Moore AL, Stringer DJ, Blevins P, Demmler-Harrison GJ, Ginsberg M, Kriner P, Waterman S, Smole S, Guevara HF, Belongia EA, Clark PA, Beatrice ST, Donis R, Katz J, Finelli L, Bridges CB, Shaw M, Jernigan DB, Uyeki TM, Smith DJ, Klimov AI, Cox NJ, , 2009. Antigenic and genetic characteristics of swine-origin 2009 A(H1N1) influenza viruses circulating in humans. Science 325: 197201.[Crossref] [Google Scholar]
  19. Bautista E, Chotpitayasunondh T, Gao Z, Harper SA, Shaw M, Uyeki TM, Zaki SR, Hayden FG, Hui DS, Kettner JD, Kumar A, Lim M, Shindo N, Penn C, Nicholson KG, , 2010. Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. N Engl J Med 362: 17081719.[Crossref] [Google Scholar]
  20. Fourment M, Mardy S, Channa M, Buchy P, , 2010. Evidence for persistence of and antiviral resistance and reassortment events in seasonal influenza virus strains circulating in Cambodia. J Clin Microbiol 48: 295297.[Crossref] [Google Scholar]
  21. Russell CA, Jones TC, Barr IG, Cox NJ, Garten RJ, Gregory V, Gust ID, Hampson AW, Hay AJ, Hurt AC, de Jong JC, Kelso A, Klimov AI, Kageyama T, Komadina N, Lapedes AS, Lin YP, Mosterin A, Obuchi M, Odagiri T, Osterhaus AD, Rimmelzwaan GF, Shaw MW, Skepner E, Stohr K, Tashiro M, Fouchier RA, Smith DJ, , 2008. The global circulation of seasonal influenza A (H3N2) viruses. Science 320: 340346.[Crossref] [Google Scholar]

Data & Media loading...

  • Received : 16 Feb 2011
  • Accepted : 06 Jun 2011
  • Published online : 01 Nov 2011

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error