Dr. Clif CleavelandThe 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.