Research Article

Dynamics of Single-City Influenza with Seasonal Forcing: From Regularity to Chaos

Figure 1

Model scheme. The 32 state variables are denoted by n + subscript. All pools other than the virus pool ( 𝑛 v i r ) and the dead-from-influenza pool ( 𝑛 d e d ) suffer from a natural mortality rate of ΞΌ (Table 1, where parameters are listed). Many categories (e.g., β€œInfected”) consist of sequential pools. The four infected pools all have (incubation) rate constants of π‘˜ i n f . Similarly, π‘˜ s i c applies to the four nonhospitalized clinically sick pools, π‘˜ h o s to the three hospitalized clinically sick pools, π‘˜ a s y to the seven asymptomatic pools, and π‘˜ d e l to the ten pools in the loss-of-immunity delay pipe. 𝑓 a s y and 𝑓 h o s are the fractions of the fluxes between 𝑛 i n f 1 and 𝑛 i n f 2 , and 𝑛 s i c 1 and 𝑛 s i c 2 , which are asymptomatic and hospitalized. πœ‡ s i c and πœ‡ h o s are the death rates (caused by flu) of the clinically sick and hospitalized pools.
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