Some discrete-time SI, SIR, and SIS epidemic models.

  title={Some discrete-time SI, SIR, and SIS epidemic models.},
  author={L. J. S. Allen},
  journal={Mathematical biosciences},
  volume={124 1},
Discrete-time models, or difference equations, of some well-known SI, SIR, and SIS epidemic models are considered. The discrete-time SI and SIR models give rise to systems of nonlinear difference equations that are similar in behavior to their continuous analogues under the natural restriction that solutions to the discrete-time models be positive. It is important that the entire system be considered since the difference equation for infectives I in an SI model has a logistic form which can… CONTINUE READING