infections
Tuberculosis (TB)
Introduction
Tuberculosis is a chronic contagious infection caused by the airborne bacteriaMycobacterium tuberculosis. It usually affects the lungs, but almost any organ can be involved. Tuberculosis is spread mainly when people breathe air contaminated by a person who has active disease. Cough is the most common symptom, but people may also have a fever and night sweats, lose weight, feel generally unwell, and, if tuberculosis affects other organs, have various other symptoms. The diagnosis usually involves a tuberculin skin test or a blood test, a chest x-ray, and examination and culture of a sputum sample. Two or more antibiotics are always given to reduce the chances of bacterial resistance. Early diagnosis and treatment plus isolation of people with active disease until they have responded to treatment help prevent tuberculosis from spreading. (See also Tuberculosis (TB) in Newborns .) Tuberculosis usually affects the lungs, although it can affect almost any organ in the body. Tuberculosis is caused by bacteria calledMycobacterium tuberculosis. Other related bacteria (called mycobacteria), such asMycobacterium bovisorMycobacterium africanum, occasionally cause a similar disease. These bacteria plusMycobacterium tuberculosisand some others are called the mycobacterium tuberculosis complex. Other Infections Caused by Bacteria Related to Tuberculosis (TB) , particularly the group called Leprosy is caused by other mycobacteria. 