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Applied Mathematics Seminar
Date/Time/Room:
Thursday (2/16/2006) at 2:00pm in 304 Pickard Hall "Why does influenza come back every winter?"Abstract: A key characteristic of Influenza epidemics is that they occur in the winter. Traditionally, this seasonality is thought to arise from seasonal changes in transmission rates. However, fitting a seasonally forced transmission model to influenza mortality time series reveals that the periodic introduction of new flu variants may also play a fundamental role. In fact, we can fit the mortality curve very well with no seasonal variation in transmission rates.In this talk, we will see that flulike cyclic dynamics can emerge from the coupling of the epidemic process (described by a deterministic compartmental model) and the viral mutation process (described by a nonhomogeneous Poisson process). While not required to generate periodicity, seasonal forcing ensures that the average period between epidemics is exactly one year.The results that I will describe suggest a variety of ways to develop tractable mathematical models that can further increase our understanding of influenza dynamics and evolution.

