Mass global movement of people is helping the spread of TB

Global trade and the number of people travelling by air have increased dramatically over the years. Passengers and crew can spread TB to each other. In many industrialized countries, at least one-half of TB cases are among foreign-born people. In the United States , nearly 40% of TB cases are among foreign-born people.

The number of refugees and displaced people in the world is also increasing. Untreated TB spreads quickly in crowded refugee camps and shelters. It is difficult to treat mobile populations, as treatment takes at least six months and should ideally be supervised.