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The New Influenza A/H1N1 Isabelle Thomas May 28-29, 2009 Brussels

The New Influenza A/H1N1 Isabelle Thomas May 28-29, 2009 Brussels. ,. HA. SCIENCE VOL 324 15 MAY 2009. Influenza virus . Famille Orthomyxoviridae …… . Genus Influenza (80-100 nm) 8 RNA segments 2 Surface glycoproteins (HA, NA) 3 Types (A, B, C)

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The New Influenza A/H1N1 Isabelle Thomas May 28-29, 2009 Brussels

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  1. The New Influenza A/H1N1 Isabelle Thomas May 28-29, 2009 Brussels ,

  2. HA SCIENCE VOL 324 15 MAY 2009

  3. Influenza virus • Famille Orthomyxoviridae……. • Genus Influenza (80-100 nm) • 8 RNA segments • 2 Surface glycoproteins (HA, NA) • 3 Types (A, B, C) Human : type A and B H1N1, H3N2, B,… Wild bird: type A all subtypes, 16H, 9N Swine : Type A H1N1, H3N2 , H1N2, …… HA NA

  4. Human Pandemic influenza viruses: reassortment is postulated to have occurred in pigs Reassortant

  5. A/Belgium/192/07 A/Belgium/198/07 A/Belgium/189/-07 A/Belgium/209/-07 A/Belgium/203/07 A/Belgium/194/07 A/Belgium/146/-07 A/Belgium/124/07 A/Belgium/122/07 A/Belgium/945/-07 A/Belgium/953/-07 A/Belgium/917/-07 A/Belgium/946/07 A/Belgium/963/07 A/Belgium96/07 A/Belgium/139/07 A/Belgium/141/07 A/Belgium/140/07 A/Belgium/144/07 A/Belgium/919/07 A/Belgium/959/-07 A/Belgium/114/07 A/Belgium/916/-07 A/Belgium/930/07 A/Belgium/931/-07 A/Belgium/206/07 A/Wisconsin/67/ 2005 A/California/7/2004 A/Fujian/ 411/ 2002 A/Wyoming/3/ 2003 2.8 2 0 Nucleotide Substitutions (x100) Influenza Viruses: Continuous evolution • Antigenic “drift”:Point mutations in the hemagglutinin gene • cause minor antigenic changes to HA. • Antigenic “drift” causes seasonal epidemics H3N2

  6. Influenza viruses : Continuous evolution • Antigenic “shift”:Emergence of a new human influenza A virus subtype (new HA subtype +/- NA). • Little or no immunity pandemic risk

  7. Surveillance of Influenza viruses : Surveillance • National : National Influenza Centers (NIC) • European : EISS, ECDC • International : WHO Objectives To monitor influenza activity To determine types and subtypes of the circulating strains To characterize circulating strains (Antigenic and Genetic characterization) To contribute to the annual determination of the influenza vaccine content To monitor resistance to antivirals To be able to detect any new human influenza virus : ex A/H7N7, A/H5N1,

  8. Surveillance of Influenza viruses : WHO Alert : 26 April New virus A/H1N1 of swine origin Cases in Mexico Cases in USA Characteristics Typable Real time PCR A Unsubtypable Real time PCR H1 seasonal Sequences of new strains rapidly available Development of real time PCR specific for SWH1N1

  9. Comparison of H1N1 Swine Genotypes in Recent Cases in the United States • H1 from American swine (>6% divergent) • N1 & M from Eurasian swine • PB1 from human origin • PA & PB2 from avian origin • NP & NS from American swine Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team. N Engl J Med 2009;10.1056/NEJMoa0903810

  10. H5N1 New H1N1

  11. Current situation • More than 8000 confirmed cases in 40 countries • 74 reported death • Most cases seem to be mild and self-limited • The virus is transmitted easily from person-to-person • Countries have rapidly developed important diagnostic capacity In Belgium • Real Time PCR A, SWH1, SWA • 150 suspected cases • 8 positive swH1N1 cases • 5 patients coming back from the USA • 3 close contact from one of the patients

  12. Evolution With Influenza viruses nothing can be predicted • How Fast will the virus spread throughout the world? • Will it become widely established? • Will the infectivity and virulence of the virus change over time?

  13. Acknowledgments • Virology • C. Gérard • Ch. Van den Poel • M. Abady • I. Fdillate • I. Micalessi • B. Brochier • D. Bauwens • Y. Ronflette • Epidemiology • S.Quoilin • F.Wuillaume

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