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Avian Influenza - Pandemic Threat ? Reinhard Bornemann.

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Presentation on theme: "Avian Influenza - Pandemic Threat ? Reinhard Bornemann."— Presentation transcript:

1 Avian Influenza - Pandemic Threat ? Reinhard Bornemann

2 1918

3 1918: Invasion of the US in 4 weeks animierte Ausbreitungskarte: http://www.pbs.org/wgbh/amex/influenza/ maps/index.htmlhttp://www.pbs.org/wgbh/amex/influenza/ maps/index.html

4 1918: special features rapid spread high attack rate unusually high morbidity and mortality in young adults

5 Influenza pandemics in history YearSubtypeDeaths 1889/90H2? H3?1 Mio. 1918/19H1N150 Mio. 1957/58H2N21-2 Mio. 1968/69H3N21 Mio. since 1977H1N1?

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7 Viral replication cyclus

8 Antigenic drift

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10 The „flu alphabet“ 8 genome segments, most important: Hemagglutinin HA (16 subtypes, H1-16) Neuraminidase NA (9 subtypes, N1-9) A / Fujian / 411 / 02 (H3N2) A / Hong Kong / 156 / 97 (H5N1) A / (animal) / (place) / (no.) / (year) (HxNx)

11 Pandemic threat: assessment methods virological / immunological potential of mutation / reassortment epidemiological conditions for an emerging pandemic

12 Virological view I animal to human infection attenuation in human host transmissibility between humans enhanced virulence

13 Virological view II recently high spread of avian flu in Asia, moving west since 1997, especially 2004, increasing human infections increasing and interacting human and animal populations increasing warnings of specialists and officials

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15 Epidemiological view transmissibility, infectiosity incubation time, duration of infectiosity „herd immunity“ after earlier epidemics ? (N2 / 1968 vs. N2 / 1957 ? effect of prior vaccination to „human“ flu ? living conditions: home, work, social contacts demography ? mobility: local, regional and international others, as vectors, surrounding conditions ?

16 Control measures ?...

17 Control measures responsible institutions „pandemic plans“ education of health professionals education of general population vaccination antiviral treatment isolation contact tracing mobility reduction(other...)

18 Vaccination interpandemic flu vaccination cycle scenario for pandemic vaccination

19 Treatment amantadine neuraminidase inhibitors: Oseltamivir, Zanamivir

20 Mathematical modelling...

21 Modelling of flu epidemics Ferguson, N.M., et al.: Strategies for containing an emerging influenza pandemic in Southeast Asia Nature online 3 August 2005 Longini, I.M., et al: Containing Pandemic Influenza at the Source Science 309: 1083-87 (August 2005)

22 Modelling parameters R 0 : number of secondary infected cases Theta (  : proportion of transmission before onset of clinical symptoms T g : disease generation time

23 Sources http://www.uni-bielefeld.de/gesundhw/ag2/infepi/ Erkrankungsbilder > Influenza Historisches > 1918


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