Right now, over two billion people have been infected with a microorganism called Mycobacterium tuberculosis. This speaks to just how infectious tuberculosis can be: The average untreated case of active tuberculosis will spread the infection to between ten and fifteen people per year.[*2] One might acquire TB on a crowded city bus, or from lying next to a sick person at night, or working near them. Less commonly, we can also contract tuberculosis from other mammals—by eating infected seal meat, or by drinking raw milk from infected cows.
