Transmission and dynamics of tuberculosis on generalized households

Tuberculosis (TB) transmission is enhanced by systematic exposure to an inf ectious individual. This enhancement usually takes place at either the home , workplace, and/or school (generalized household). Typical epidemiological models do not incorporate the impact of generalized households on the stud y of disease dynamics. Models that incorporate cluster (generalized househo ld) effects and focus on their impact on TB's transmission dynamics are dev eloped. Detailed models that consider the effect of casual infections, that is, those generated outside a cluster, are also presented. We find express ions for the Basic Reproductive Number as a function of cluster size. The f ormula for R-O, separates the contributions of cluster and casual infection s in the generation of secondary TB infections. Relationships between clust er and classical epidemic models are discussed as well as the concept of cr itical cluster size. (C) 2000 Academic Press.