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SUMMARY:Timing of emergence and epidemic peak of novel influenza strains -
  Ryosuke Omori - Kyushu University\, Japan
DTSTART:20100610T153000Z
DTEND:20100610T163000Z
UID:TALK25207@talks.cam.ac.uk
CONTACT:Prof. Julia Gog
DESCRIPTION:Influenza has large antigenic diversity and rapid evolution\, 
 and it can keep escaping from host immunity. To understand the evolutionar
 y dynamics of influenza with host immune reaction\, we developed two model
 s : i) a deterministic epidemiological model with discrete epidemic season
 s used to study the initial phase of the evolutionary branching process as
 sociated with two antigenic escape mutants derived from a common ancestral
  strain ii) a multi-strain SIR individual based model. With these models w
 e found that:\n  (1). The time at which a new strain appears relative to t
 he epidemic peak of an existing strain is important because it determines 
 the environment the emergent mutant experiences in terms of the short term
  immune profile of the host population. Strains are more likely to coexist
 \, and hence to establish a new clade in the viral phylogeny\, when there 
 is a significant time overlap between their epidemics.\n  (2) In a year\, 
 the most frequent emergence time of successful strain (the strain will pro
 duce new mutant strain) is early stage of epidemic season.  The duration f
 rom emergence time to maximum prevalence is over one year. This has implic
 ation for the prediction of epidemic strain in future.
LOCATION:MR14\,  Centre for Mathematical Sciences\, Wilberforce Road\, Cam
 bridge
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