The largest California outbreak of tuberculosis in a decade is happening in Los Angeles right now, and the Centers for Disease Control has finally dispatched a team of scientists to help LA-area authorities try to control it. The locus of the outbreak, which involves a strain of TB unique to LA, is the city's notorious Skid Row, the small constellation of streets in downtown where Southern California's most downtrodden citizens—homeless people, prostitutes, heroin addicts, combinations of all three—congregate in such close quarters that a disease outbreak was probably inevitable. Since 2007, 11 people have died of TB in LA County, according to the LA Times. In the latest outbreak, 60 of the 78 cases reported to authorities were homeless people living on or near Skid Row.
TB, which is airborne, is simple to pass along, especially in the homeless community, with its transience, lack of hygiene, and lack of medical care. It's treatable, but if it's not dealt with it can be deadly, particularly in people already infected with HIV. Owing to that fact, local and federal health authorities are now searching for nearly 4,700 other people who were probably exposed to the disease sometime recently.
Tuberculosis rates are going down nationally and in LA County at large, but they are on the rise amongst LA's homeless population. TB is currently the second-largest killer infectious agent worldwide, after HIV, according to the World Health Organization, and the CDC says one-third of people on earth are infected with the disease. Most of those infections happen outside the United States, but TB is largely an illness of poverty [PDF], a crisis America has yet to solve.