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OCCURENCE OF INFLUENZA PANDEMICS AND EPIDEMICS: ANTIGENIC SHIFT AND DRIFT

OCCURENCE OF INFLUENZA PANDEMICS AND EPIDEMICS: ANTIGENIC SHIFT AND DRIFT. Occurrence of influenza pandemics and epidemics. Incidence of clinically manifest influenza Mean level of population antibody vs A HxNx Mean level of population antibody vs A HyNy. Pandemic. Pandemic.

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OCCURENCE OF INFLUENZA PANDEMICS AND EPIDEMICS: ANTIGENIC SHIFT AND DRIFT

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  1. OCCURENCE OF INFLUENZA PANDEMICS AND EPIDEMICS: ANTIGENIC SHIFT AND DRIFT

  2. Occurrence of influenza pandemics and epidemics Incidence of clinically manifest influenza Mean level of population antibody vs A HxNx Mean level of population antibody vsA HyNy Pandemic Pandemic Interpandemic Period Epidemic Epidemic Mean population antibody level Incidence Epidemic 1 2 3 4 5 6 7 8 9 10 11 12 Jahre Introduction of hypothetical A HyNy major (new subtype) variant A HxNx disappears. Introduction ofa hypothetical A HxNx variant Significant minor variation A HxNx mayoccur at any of these points. Epidemicsmay or may not be associated with suchvariations.. Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases, 5th ed. 2000:1829. Modified from Kilbourne ED. Influenza. 1987:274, with permission.

  3. Murray CJL et. al: Estimation of potential global pandemic influenza mortality on the basis of vital registry datafrom the 1918–20 pandemic: a quantitative analysis. The Lancet, Vol. 368, 2006; 2211 Global mortality during an influenza pandemic Median excess mortality by age and sex for the 1918-20 pandemic, based on data from 13 countries with avialable complete age-specific mortality data

  4. Type B Type A H1N1 H2N2 H3N2 H5N1 A constantly mutating virus

  5. Mutation by antigene drifting RNA Hemagglutinin Neuraminidase Antibodies Sialic acid

  6. Mutation by antigene shifting – Influenza Type A A new subtype is born, which may have pandemicpotential A novel HA or NA subtype from avian genome is incorporated inan existing virus genome.

  7. By courtesy of Dr. T.D. Szucs, University of Zurich, Switzerland

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