EpiDynamics (version 0.3.1)

SIS: Simple SIS model (P 2.5).

Description

Solves a simple SIS model without births or deaths.

Usage

SIS(pars = NULL, init = NULL, time = NULL, ...)

Arguments

pars

vector with 2 values: the transmission and recovery rates. The names of these values must be "beta", and "gamma", respectively.

init

vector with 2 values: the initial proportion of proportion of susceptibles and infectious. The names of these values must be "S" and "I", respectively.

time

time sequence for which output is wanted; the first value of times must be the initial time.

...

further arguments passed to ode function.

Value

list. The first element, *$model, is the model function. The second, third and fourth elements are the vectors (*$pars, *$init, *$time, containing the pars, init and time arguments of the function. The fifth element *$results is a data.frame with up to as many rows as elements in time. First column contains the time. Second and third columns contain the proportion of susceptibles and infectious.

Details

This is the R version of program 2.5 from page 39 of "Modeling Infectious Disease in humans and animals" by Keeling & Rohani.

All parameters must be positive and S + I <= 1.

References

Keeling, Matt J., and Pejman Rohani. Modeling infectious diseases in humans and animals. Princeton University Press, 2008.

See Also

ode.

Examples

# NOT RUN {
# Parameters and initial conditions.
parameters <- c(beta = 1.4247, gamma = 0.14286)
initials <- c(S = 1 - 1e-06, I = 1e-06)

# Solve and plot.
sis <- SIS(pars = parameters, init = initials, time = 0:70)
PlotMods(sis)

# }