Endemic Thresholds and Stability in a Class of Age-Structured Epidemics

An age-structured epidemic model is analyzed when the fertility, mortality and removal rates depend on age. For certain general forms of the force of infection terms, endemic threshold criteria are derived and the stability of steady state solutions is determined. The relation between age-structured models of this type and catalytic curve models of epidemics is derived. The possibility of identifying vertically transmitted diseases from the catalytic curve is demonstrated.