Stage-structured epidemic models provide a way to connect the interacting
processes of infection and demography. Reproduction and development
can replenish the pool of susceptible hosts, and demographic structure leads
to heterogeneous transmission and disease risk. Epidemics, in turn, can increase
mortality or reduce fertility of the host population. Here we present
a framework that integrates both demography and epidemiology in models
for stage-structured epidemics. We use the vec-permutation matrix approach
to classify individuals jointly by their demographic stage and infection status.
We describe demographic and epidemic processes as alternating in time
with a periodic matrix models. The application of matrix calculus to this
framework allows for the calculation of R0 and sensitivity analysis.