Model and treatment schematic.

<p>Model schematic: individuals are born healthy and may subsequently acquire latent TB (non-MDR or MDR) infections through transmission. Individuals who develop active TB disease may subsequently seek treatment. Treatment schematic: individuals with active TB may enter public- or private-sector treatment (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089822#pone.0089822.s001" target="_blank">File S1</a> for details). Individuals in private treatment are not cured but are exposed to a risk of developing MDR TB (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089822#pone.0089822.s001" target="_blank">File S1</a> for details on modeling exposure to the effects of private-sector treatment on MDR generation). Public sector treatment is modeled according to the DOTS protocols: Patients with prior treatment enter category II treatment, and those who test positive for MDR enter MDR treatment (or Category IV treatment/DOTS-Plus) six months after MDR testing if MDR treatment is available. For patients whose non-MDR TB is not cured by treatment, there is a chance that they develop treatment-generated MDR TB.