SIR model: swine flu

The SIR model tries to model influenza epidemics. Here, we try to medel the spreading of the swine flu.

• According to the CDC Centers of Disease Control and Prevention: "Adults shed influenza virus from the day before symptoms begin through 5-10 days after illness onset. However, the amount of virus shed, and presumably infectivity, decreases rapidly by 3-5 days after onset in an experimental human infection model." So, here we set [math]\gamma=1/7[/math] as the recovery rate. This means, on average an infected person sheds the virus for 7 days.
• In Modeling influenza epidemics and pandemics: insights into the future of swine flu (H1N1) the authors estimate the reproduction rate [math]R_0[/math] of the virus to be about 2. For the SIR model this means:

the reproduction rate [math]R_0[/math] for influenza is equal to the infection rate of the strain ([math]\beta[/math]) multiplied by the duration of the infectious period ([math]1/\gamma[/math]), i.e.

[math]\beta = R_0\cdot \gamma[/math]