Tuberculosis (TB) transmission is enhanced by a systematic and long exposure to an infectious individual. This process usually takes place within a cluster of individuals that includes the home, the workplace, and/or the school. Typical TB models ignore this cluster effect. In this work, we present new models for TB transmission that incorporate cluster effects on the transmission dynamics of TB. Our model considers the effect of casual infections, that is, those generated outside a cluster, versus those generated in a cluster. We find expressions for the Basic Reproductive Number as a function of cluster size. Our formula helps diferentiate the contributions of cluster vs. casual infections to the generation of secondary infections. The relationship between cluster and typical epidemic models is discussed.
Joint work with Juan Aparicio, and Carlos Castillo-Chavez.