What is Tuberculosis?

Tuberculosis (TB) is an infectious disease that primarily affects the lungs. Although the number of infections in the U.S. has declined since 1993, it remains a concern. Many strains of tuberculosis are resistant to the drugs used to treat it. People with active tuberculosis infections need to take several types of medication for months to eradicate the disease and prevent further development of antibiotic resistance.

The bacteria that cause tuberculosis spread in microscopic droplets released into the air via coughing and sneezing. Transmission can happen when a patient in the untreated, active state of tuberculosis coughs, laughs, sneezes, speaks, spits or takes any action that involves breathing air out from the lungs. Most people with active TB who receive appropriate medical treatment for at least two weeks are no longer contagious.

The tuberculin skin test (TST) is a screening test for TB. Its process has two parts: the placement, and the reading.

An alternative to the TST is a blood test, called the QuantiFERON-Tb Gold test. Both this test and the TST are screening tests.

TB is only contagious in its active state when it affects the lungs. Treating and preventing latent TB from becoming active can stop tuberculosis transmission to others. There are a few ways to help prevent the spread of TB:

• Isolate yourself. Stay home from work or school. Sleep alone in a room during the first few weeks while active tuberculosis is treated.
  
• Use a tissue to cover your mouth when coughing, laughing or sneezing: Place the dirty tissue in a bag, seal it and throw it away.
  
• Ventilate the room. Tuberculosis germs are more likely to spread in small, enclosed spaces where air stagnates. Refresh the room air by opening windows and using a fan to blow indoor air outside.
  
• Wear a mask. During the first three weeks of treatment, reduce transmission by wearing a surgical mask while you’re near other people.

Although the body may harbor the bacteria that cause TB, the immune system usually can prevent you from becoming sick. There are two distinct states of tuberculosis infection:

• Active TB: This state causes illness and is contagious in most cases. It may occur in the first few weeks following infection with the TB bacteria, or it could happen years later.
  
• Latent TB (inactive TB or TB infection): You’re infected, but the bacteria remain dormant and cause no symptoms. Latent TB is not contagious. If untreated it can become active TB.

What symptoms can occur with TB?

Many patients who develop a TB infection experience some of the following symptoms:

• Chest pain or pain during breathing or coughing
• Chills or night sweats
• Chronic coughing lasting three weeks or more
• Coughing up blood
• Fever
• Loss of appetite
• Unexpected weight loss and fatigue

Tuberculosis can also affect other parts of the body, including the brain, kidneys or spine. When TB occurs away from the lungs, symptoms will vary according to the organs affected. For example, tuberculosis in the kidneys may lead to blood in your urine. If it’s in the spine, it may produce back pain.

The risk of contracting tuberculosis increases for people either living in or traveling to areas with high incidences of tuberculosis, including:

• Africa
• Asia
• Caribbean islands
• Eastern Europe
• Latin America
• Russia