Tuberculosis (TB) is a serious bacterial infection that primarily affects the lungs and respiratory system, though it can invade any organ. It’s a contagious infection that can be spread in the water droplets of a cough or sneeze.

There are two main types of TB: latent TB infection (LTBI) and active TB disease (sometimes just referred to as TB disease).

Latent TB means you have been infected with TB, but have no symptoms. If you have latent TB, a lung X-ray will not show active disease.

TB disease, however, is characterized by symptoms that include coughing and fever. This type is contagious and dangerous. It can spread from the lungs to other parts of the body.

TB is spread through the air. The droplets containing the bacteria must be inhaled for the infection to spread from one person to another. This means that being near someone with TB disease when they cough, sneeze, or even talk close to your face for an extended period of time puts you at risk for infection.

Kissing, hugging, or shaking hands with a person who has TB doesn’t spread the disease. Likewise, sharing bed linens, clothes, or a toilet seat isn’t how the disease spreads either.

However, if you’re in close quarters over a period of time with someone who has TB, you could catch the disease from breathing air that’s been saturated with the bacteria.

People living and working with someone who has TB disease are much more likely to become infected than someone in the general public who has a fleeting encounter with someone carrying TB disease.

Exposure to the TB bacteria isn’t always enough to develop the infection. Your body may be able to fight it off.

One of the key factors that raises your risk of becoming infected after exposure is if you have a weakened immune system. You may be at increased risk for TB if you:

TB is also more common in certain parts of the world, including Russia, South America, and Africa. You may be at increased risk if you live in areas with more incidences of TB or if you travel to these areas.

Working in healthcare also raises your TB risk, as does smoking and drug abuse.

If you’ve been infected with the bacteria, you may develop symptoms within a few weeks, or it could be years before you see signs of infection.

Reducing your exposure to people who have active TB is one way to reduce your risk, but this isn’t always possible.

If you’re traveling to a foreign country where TB continues to be a serious public health problem, get up-to-date information about travel warnings or vaccination requirements from the Centers for Disease Control and Prevention.

When traveling to areas with a high prevalence of TB, try to avoid crowded places if possible. Other ways to reduce your exposure include:

  • Keeping your room well-ventilated. TB bacteria tend to spread faster in more confined spaces with less outside air.
  • Staying home for several weeks or months after you have started TB treatment.

There is a TB vaccine called the Bacillus Calmette-Guerin (BCG) vaccine. It’s not widely used in the United States. It’s more commonly used in countries with a higher rate of TB among babies and children.

If you’re at increased risk for TB, BCG may help reduce your risk.

When symptoms are present, they usually include coughing that lasts for more than a few weeks. The coughs tend to produce phlegm, and it may be flecked with blood at times or be pink, suggesting bleeding and irritation.

Chest pain, especially when breathing deeply or coughing, is also a common symptom.

Other symptoms may include:

  • fatigue
  • unexplained weight loss
  • fever
  • chills
  • loss of appetite

If TB has spread to another part of the body, your symptoms may change. An infection that has reached the back, for example, may cause back pain.

Once a diagnosis of TB disease is confirmed through TB skin tests, blood tests, and analysis of your sputum, you should begin treatment as soon as possible. Your sputum is the mix of saliva and mucus you cough up when sick.

There are several different medications you may be prescribed based on the type of TB detected. The most frequent combination for active TB includes the antibiotics isoniazid, rifampin, ethambutol, and pyrazinamide.

The course of the drug you take will depend on several factors, such as your age and how far the disease has progressed. But the typical course for TB antibiotics is about six to nine months.

There’s no guarantee that latent TB won’t turn into TB disease, but being proactive about treatment and following through on the entire course of antibiotics may help you recover.

TB is a contagious disease that spreads through the air. Reducing your exposure to people with the condition may help reduce your risk. There’s also a vaccine that may help reduce your risk.

Though it is not in every country, tuberculosis remains one of the top 10 causes of death around the world. If you suspect you’ve developed TB, seek immediate medical help.