Volume 88, Issue 5
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



We describe virus variations from patients with influenza-like illness before and after the appearance of influenza A(H1N1)pdm09 in Kenya during January 2008–July 2011. A total of 11,592 nasopharyngeal swabs were collected from consenting patients. Seasonal influenza B, A/H1N1, A/H3N2, A/H5N1, and influenza A(H1N1)pdm09 viruses were detected by real-time reverse transcription–polymerase chain reaction. Of patients enrolled, 2073 (17.9%) had influenza. A total of 1,524 (73.4%) of 2,073 samples were positive for influenza A virus and 549 (26.6%) were positive for influenza B virus. Influenza B virus predominated in 2008 and seasonal A(H1N1) virus predominated in the first half of 2009. Influenza A(H1N1)pdm09 virus predominated in the second half of 2009. Influenza A/H3N2 virus predominated in 2010, and co-circulation of influenza A(H1N1)pdm09 virus and influenza B virus predominated the first half of 2011. The reduction and displacement of seasonal A(H1N1) virus was the most obvious effect of the arrival of influenza A(H1N1)pdm09 virus. The decision of the World Health Organization to replace seasonal A(H1N1) virus with the pandemic virus strain for the southern hemisphere vaccine was appropriate for Kenya.


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  1. Lindstrom SE, Cox NJ, Klimov A, , 2004. Genetic analysis of human H2N2 and early H3N2 influenza viruses, 1957–1972: evidence for genetic divergence and multiple reassortment events. Virology 328: 101119.[Crossref] [Google Scholar]
  2. Webster RG, , 1998. Influenza: an emerging disease. Emerg Infect Dis 4: 436441.[Crossref] [Google Scholar]
  3. Webster RG, Bean WJ, Gorman OT, Chambers TM, Kawaoka Y, , 1992. Evolution and ecology of influenza A viruses. Microbiol Rev 56: 152179. [Google Scholar]
  4. 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 18: 26052615. [Google Scholar]
  5. Palese P, Wang TT, , 2011. Why do influenza subtypes die out? A hypothesis. mBio 2: pii: e00150–11.[Crossref] [Google Scholar]
  6. Centers for Disease Control and Prevention, 2009. Outbreak of swine-origin influenza A (H1N1) virus infection–Mexico, March–April 2009. MMWR Morb Mortal Wkly Rep 58: 467470. [Google Scholar]
  7. Blyth CC, Kelso A, McPhie KA, Ratnamohan VM, Catton M, Druce JD, Smith DW, Williams SH, Huang QS, Lopez L, Schoub BD, Venter M, Dwyer DE, , 2010. The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009. Euro Surveill 15. [Google Scholar]
  8. Broor S, Krishnan A, Roy DS, Dhakad S, Kaushik S, Mir MA, Singh Y, Moen A, Chadha M, Mishra AC, Lal RB, , 2012. Dynamic patterns of circulating seasonal and pandemic A(H1N1)pdm09 influenza viruses from 2007–2010 in and around Delhi, India. PLoS ONE 7: e29129.[Crossref] [Google Scholar]
  9. Broor S, Gupta S, Mohapatra S, Kaushik S, Mir MA, Jain P, Dar L, Lal RB, , 2011. Emergence of 2009A/H1N1 cases in a tertiary care hospital in New Delhi, India. Influenza Other Respi Viruses 5: e552e557.[Crossref] [Google Scholar]
  10. World Health Organization, 2011. Influenza Transmission Zones. Available at: http://www.who.int/influenza/surveillance_monitoring/updates/EN_GIP_Influenza_transmission_zones.pdf. Accessed July 10, 2012. [Google Scholar]
  11. Bulimo WD, Mukunzi S, Achilla R, Opot BH, Osuna F, Majanja J, Wadegu M, Wurapa EK, , 2012. Were the WHO-recommended human influenza vaccine formulations appropriate for Kenya during the 2010–2011 season? Inferences from the HA1 gene analysis. Afr J Pharmacol Ther 1: 4654. [Google Scholar]
  12. Laguna-Torres VA, Gomez J, Aguilar PV, Ampuero JS, Munayco C, Ocana V, Perez J, Gamero ME, Arrasco JC, Paz I, Chavez E, Cruz R, Chavez J, Mendocilla S, Gomez E, Antigoni J, Gonzalez S, Tejada C, Chowell G, Kochel TJ, Peru Influenza Working Group; , 2010. Changes in the viral distribution pattern after the appearance of the novel influenza A H1N1 (pH1N1) virus in influenza-like illness patients in Peru. PloS One 5: e11719.[Crossref] [Google Scholar]
  13. Tang JW, Lee CK, Lee HK, Loh TP, Chiu L, Tambyah PA, Koay ES, , 2010. Tracking the emergence of pandemic Influenza A/H1N1/2009 and its interaction with seasonal influenza viruses in Singapore. Ann Acad Med Singapore 39: 291294. [Google Scholar]
  14. Bulimo WD, Gachara G, Opot BH, Murage MW, Wurapa EK, , 2012. Evidence in Kenya of reassortment between seasonal influenza A(H3N2) and influenza A(H1N1)pdm09 to yield A(H3N2) variants with the matrix gene segment of A(H1N1)pdm09. Afr J Pharmacol Ther 1: 17. [Google Scholar]
  15. Nishiura H, Castillo-Chavez C, Safan M, Chowell G, , 2009. Transmission potential of the new influenza A(H1N1) virus and its age-specificity in Japan. Euro Surveill 14. [Google Scholar]
  16. Fraser C, Donnelly CA, Cauchemez S, Hanage WP, Van Kerkhove MD, Hollingsworth TD, Griffin J, Baggaley RF, Jenkins HE, Lyons EJ, Jombart T, Hinsley WR, Grassly NC, Balloux F, Ghani AC, Ferguson NM, Rambaut A, Pybus OG, Lopez-Gatell H, Alpuche-Aranda CM, Chapela IB, Zavala EP, Guevara DM, Checchi F, Garcia E, Hugonnet S, Roth C, WHO Rapid Pandemic Assessment Collaboration; , 2009. Pandemic potential of a strain of influenza A (H1N1): early findings. Science 324: 15571561.[Crossref] [Google Scholar]
  17. Chowell G, Miller MA, Viboud C, , 2008. Seasonal influenza in the United States, France, and Australia: transmission and prospects for control. Epidemiol Infect 136: 852864. [Google Scholar]
  18. Centers for Disease Control and Prevention, 2009. Introduction and transmission of 2009 pandemic influenza A (H1N1) Virus–Kenya, June–July 2009. MMWR Morb Mortal Wkly Rep 58: 11431146. [Google Scholar]
  19. Othieno N, , 2006. Inequality in Kenya's health sector. Nairobi, Kenya: Society for International Development. Regional Office for Eastern Africa. Readings on Inequality in Kenya: Sectoral Dynamics and Perspectives, 97155. [Google Scholar]
  20. World Health Organization, 2011. Recommended Composition of Influenza Virus Vaccines for Use in the 2012 Southern Hemisphere Influenza Season. Available at: http://www.who.int/influenza/vaccines/virus/recommendations/2011_09_recommendationpdf2011. [Google Scholar]
  21. World Health Organization, 2012. Influenza, FluNet Charts. Available at: http://www.who.int/influenza/gisrs_laboratory/flunet/charts/en/index.html. [Google Scholar]

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  • Received : 06 Mar 2012
  • Accepted : 13 Dec 2012
  • Published online : 01 May 2013

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