ANALYSIS OF AN AGE-DEPENDENT SI EPIDEMIC MODEL WITH DISEASE-INDUCED MORTALITY AND PROPORTIONATE MIXING ASSUMPTION: THE CASE OF VERTICALLY TRANSMITTED DISEASES.

An SI epidemic model for a vertically as well as horizontally transmitted disease is investigated when the fertility, natural mortality, and disease-induced mortality rates depend on age and the force of infection corresponds to a special form of intercohort transmission called proportionate mixing. We determine the steady states and obtain explicitly computable threshold conditions, and then perform stability analysis. [ABSTRACT FROM AUTHOR]