TB simulation overview.
This figure illustrates our individual-based simulation model, following a hypothetical population for three consecutive (annual) time steps (Time = t, t+1, t+2). All infected individuals carry a single strain of TB (A, B, or C in this example). At each time step, three processes are modeled: 1. Transmission: upon successful contact, actively infected individuals can transmit the disease (marked by their strain type) to other people in the population. 2. Progression: other TB states are updated as shown in the left panel, including stabilization of latency, re-infection, diagnosis, and treatment, and relapse. Individuals who are diagnosed have their strain type recorded for analysis as they move from the active to the recovered state. 3. DNA fingerprint replacement: a random number of individuals in the late latency state are selected to carry new and unique fingerprints (strains), to maintain genetic diversity and account for processes such as mutation, migration, and infection from outside the population.