The young man experienced progressive fatigue. Night sweats developed. A deepening cough produced thick sputum, sometimes with bloody streaks. Microscopic study of his sputum showed microbes typical of Mycobacterium tuberculosis (Mtb). A bacterial culture confirmed the diagnosis. Chest X-ray revealed an abnormal density in his right lung. Several months of medication eradicated the infection and restored his health.
In 2016, an estimated two billion of the world's population were infected with Mtb. Most had no symptoms. More than ten million developed active tuberculosis. One and a half million people died from the disease.
Tuberculosis is a major, contributing factor to deaths of people infected with human immunodeficiency virus (HIV).
Because of our excellent public health system, the US has been largely excluded from this continuing international epidemic. In 2016, 9272 cases of active tuberculosis were reported along with 479 deaths.
Mtb is typically acquired by inhaling droplets of sputum from the coughs or sneezes of a person with active, pulmonary tuberculosis. A small number will develop a respiratory infection that will progress to full-blown tuberculosis. Most people will experience no symptoms. Mtb will be contained but not eradicated by their immune system. They have latent tuberculosis. Up to ten percent of persons with latent disease will eventually develop progressive tuberculosis. Advancing age, malnutrition, and treatment with certain cancer chemotherapies or drugs that modify the immune system can activate latent infection, which can spread throughout the body.
A tuberculin skin test or a blood analysis can determine if a person has latent tuberculosis. Treatment to eradicate the infection can be selected from a variety of options.
Symptoms consistent with pulmonary tuberculosis were described in Ancient Greece. Galen, the renowned physician of Ancient Rome, recognized the contagious nature of the illness. The disease intensified as people congregated in cities. Prisons, monasteries, and cramped workshops, factories, and living quarters became hotbeds of infection.
The list of victims of tuberculosis include French playwright Moliere, writers Robert Lewis Stevenson, Anton Chekov, D.H. Lawrence, Franz Kafka, Emily, Ann and Charlotte Bronte and poet John Keats. Twentieth-century survivors of the disease include Margaret Sanger and Walker Percy.
German physician, researcher, and 1905 Nobel Laureate, Robert Koch, isolated the Mtb bacillus in the 1880s. His efforts to develop a cure failed.
In the early decades of the 20th century, victims who could afford the costs, sought recovery in sanitaria situated in mountain retreats, which emphasized rest and nutritious diet. Patients might reside in the facility for years until they regained their health. A variety of surgical procedures involving removal or collapse of affected lung tissue failed. Many states and cities established specialized, tuberculosis hospitals where patients were quarantined until they either improved or died.
The discovery of the antibiotic, Streptomycin, in the mid-1940s, offered a fleeting hope of a cure. Victims improved but suffered severe, permanent hearing loss. The discovery of Isoniazid in 1945 ushered in an array of drugs which can eradicate Mtb. Each treatment requires months of consistent taking of one or more medications, making treatment especially challenging in homeless or migrant populations. Sporadic taking of medications can lead to the emergence of resistant strains of Mtb. Each medication has potentially serious side-effects.
The progressive reduction of tuberculosis in the US represents a success story of basic science, clinical medicine, and public health services. Expanding that success to the rest of the world is a daunting challenge.
The good work of public health services on national, state, and local levels goes largely unnoticed. Their budgets offer inviting targets for politicians whose sole concern is slashing taxes. US contributions of funds and expertise to international public health efforts are also criticized by those with little understanding of the threats posed by epidemic diseases. Older diseases persist. New ones arise. The challenges of defending the public's health are unrelenting.
The Centers for Disease Control and Prevention (www.cdc.gov) is the definitive site for information on tuberculosis and other diseases.
Clif Cleaveland, M.D., is a retired internist and former president of the American College of Physicians. Email him at firstname.lastname@example.org.