Tuberculosis (TB) is among the oldest recorded diseases in human history. Infection with Mycobacterium tuberculosis occurs when the bacteria are expelled- along with moisture from a diseased person's respiratory system while coughing, sneezing, speaking, singing, or exhaling-and are inhaled into another person's lungs. Transmission of TB through close human contact is common; about one third of the world is infected with TB. Only a minority of those infected will develop active TB disease, which is deadly if untreated or improperly treated. Progression from infection to active disease is much more likely among people with compromised immune systems, such as the very young, the very old, and those with HIV infection. TB has long been linked in the popular imagination with alcoholism and drug addiction, and in fact heavy drinkers have an elevated risk of TB disease, as do injection and other drug users. Furthermore, substance users tend to come from the marginalized groups most vulnerable to TB, including the homeless, those living in poverty, and those without access to health care. Because in the United States the disease disproportionately affects substance users, they have been a particular target of public health efforts to control TB. Since the late 19th century, these efforts have been directed by state and local governments acting on their legal authority to protect the public's health and safety. Modern TB control efforts consist essentially of a dual strategy of ensuring a cure for every case of TB disease, while at the same time confining active cases in some manner, in order to reduce contact with others and thus transmission of TB while the patient is infectious.
TB is often described as a "social disease." Some use the term simply to recognize the influence of malnutrition, crowded or otherwise inadequate housing, and other aspects of poverty on progression from infection to active disease. Others go further to argue that the ultimate cure for TB must also be social and should ameliorate the social problems that give rise to the disease. Modern TB control efforts in the United States, as well as globally, have largely recognized that it is essential to address the socio-economic context of TB disease in order to effect a cure, although the extent to which public health officials are committed to solving social ills has varied over time and place.
Public Health Responses
Early public health responses to TB called for removing its victims from their social environment, often to sanatoria, where bed rest, fresh air, and a nourishing diet were usually all that was offered toward a cure. The discovery in the late 19th century that TB was transmitted through close human contact did not dispel popular beliefs linking susceptibility to TB to poverty and sometimes to the immorality and depravity thought to flourish in poverty. Rather, the understanding of the disease as...