Which strains of tuberculosis are the most infectious?

Highly localized TB strains are less infectious in cosmopolitan cities and more likely to infect people from the geographic area that is the strain's natural habitat. The research provides the first controlled evidence that TB strains may evolve with their human hosts, adapting to be more infectious to specific populations. The findings offer new clues for tailoring preventive treatments after exposure to TB based on affinity between strains host populations.