Left untreated, that person will infect, on average, between 10 and 15 people per year. Risk of infection is greatest for those with high levels of exposure to the bacillus and those with weakened immune systems. For example, prisoners in overcrowded and poorly ventilated conditions contract TB at alarming rates. For those who are affected by malnutrition, chronic illness, or HIV infection, the risk of progressing to active TB from TB infection skyrockets. Effective treatment for TB is available, involving lengthy multiple-drug regimens.
Proper treatment is difficult to obtain in developing countries, where it is needed most.