Tuberculosis (TB) is a contagious disease caused by the airborne bacterium Myobacterium tuberculosis. It usually affects the lungs, although it can spread to other organs in the body. In many cases, it can be successfully treated with a course of antibiotics. It is a relatively rare disease in the United States, although some groups of people may have an increased risk of contracting TB, including:

• People with HIV or AIDS
  
  
• People who were born in a country with high TB rates
  
  
• Older adults
  
  
• People who live or work in poverty and are medically underserviced
  
  
• Substance abusers

Not everyone who encounters the TB bacteria will become sick. In most people, the TB bacteria are fought by the immune system and isolated from the rest of the body by special white blood cells. Once TB bacteria have been isolated, they can survive in a dormant state (latent TB) within the body for many years. Latent TB produces no symptoms and people with the dormant bacteria are not contagious. However, if a person’s immune system weakens, the bacteria may become reactivated and multiply in the lungs. When the bacteria are actively causing disease, it is called active TB. Active TB is highly contagious and can produce symptoms such as:

• Cough that lasts for over three weeks
  
  
• Discolored or bloody sputum (mucus coughed up from the lungs)
  
  
• Night sweats
  
  
• Chills
  
  
• Fatigue
  
  
• Mild fever
  
  
• Loss of appetite that may cause weight loss
  
  
• Pain in the chest while breathing or coughing

It is important that people who suspect they have been infected with TB consult their physician for a skin test. Active TB remains contagious for at least two weeks after medication is started. People diagnosed with active TB should stay at home and limit their contact with others until a physician indicates it is safe to resume contact with others.

TB is often diagnosed using a skin test. If the results are positive, the physician may conduct additional tests to confirm the extent of the infection. Once diagnosed, TB is treated with a combination of different antibiotics taken for between six months and a year. It is very important that people with TB take their medication for the full course. Failure to take the entire course of antibiotics can lead to antibiotic resistance, which makes treatment far more difficult.

Treating TB in patients with HIV can be especially difficult. Many of the medications used to treat TB interfere with the medications used to treat HIV. Also, studies have shown that TB bacteria may hasten the progression of HIV into AIDS.

Unfortunately, there is little that individuals can do to prevent contracting TB if they have close contact with someone who is infected. For this reason, people should avoid contact with people known to have TB and take protective measures if caring for an infected person. People with TB can avoid spreading the disease by practicing good personal hygiene and taking all prescribed medication. There is no effective vaccine available for TB.