Article révisé par les pairs
Résumé : A chain-binomial deterministic model for the spread of an infectious disease of the S-I-S type is formulated that accounts explicitly for the distribution of the number of contacts made by each susceptible during one time interval. Under certain hypotheses, a threshold theorem for endemicity is derived, bounds for the endemic level are constructed, and the transient behavior of the epidemic process is investigated. © 1986.