What Is Tuberculosis (TB)?

Tuberculosis caused 1.5 million deaths in 2013 alone. Learn the symptoms and treatment of one of the deadliest, most contagious diseases in the world.

Sanaz Majd, MD
4-minute read
Episode #171


If you’ve been watching the news closely, you may have heard a little something about the high rates of tuberculosis (TB) infection around the world. Unfortunately, this news was likely trumped by the recent Ebola coverage. But don't let that fool you. TB is actually a much bigger infectious disease than Ebola. 

See also: Should You Worry About the Ebola Outbreak?

The World Health Organization (WHO) just released its 2014 Global Tuberculosis Report. It reported over 9 million cases of active TB in 2013 alone. The infection caused 1.5 million deaths that year.  These numbers make TB one of the deadliest contagious diseases ever.  Compare that to Ebola's 5,000 deaths and you get a very different perspective.

We all need to be aware of TB, as it is one of the most contagious diseases that we know of, and one with some very grave consequences if left untreated.  I have seen a few cases of active TB in my Southern California practice recently, so I think it’s crucial for everyone to be aware of what TB is, what symptoms it produces, and how it’s spread and treated.

What Is Tuberculosis (TB)?

TB is caused by the bacteria Mycobacterium tuberculosis.  It often affects the lungs of those with an active infection and is spread through the air via air droplets when infected people cough or sneeze into the air. 

Once this infected air droplet is inhaled, the bacteria is held captive in our bodies and becomes what we call “dormant” – that is, it literally sleeps and is referred to as “latent TB.”  Latent TB is considered quite common – in fact, up to one third of people in the world are said to have latent TB (yep, one third!).  Those with latent TB do not feel sick and cannot spread the infection to others.  In fact, those with latent TB often don’t even know they have it until they undergo routine screening.

The more spooky part, however, is that in 5-10% of patients with latent TB, at some point the bacteria reactivates and causes potentially nasty symptoms – this is called “active TB.”  Even scarier, those with active TB can spread the infection easily to anyone they come into contact with.

Who Gets TB?

Like the common cold or flu virus, anyone can catch TB as long as they are exposed to someone with an active infection who spreads it through the air (via coughing or sneezing).  However, certain populations are deemed higher risk of contracting TB. They are:

  • The elderly
  • People with HIV
  • People who suffer from malnutrition
  • People taking drugs that suppress the immune system (as in the treatment of Lupus, severe Psoriasis, or Rheumatoid Arthritis)
  • Chronic corticosteroid users
  • Chemotherapy patients
  • People with Diabetes

Symptoms of Active TB

Again, latent TB displays no symptoms.  But for active TB, symptoms can be rather vague and mild for some patients, which can make TB difficult to diagnose in areas of the world with a lower incidence, such as the United States.  However, anyone with the following symptoms, especially if persistent and/or accompanied by any of the TB risk factors I outlined earlier, should be considered for TB screening:


Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.

About the Author

Sanaz Majd, MD

Dr. Sanaz Majd is a board-certified Family Medicine physician who graduated from Drexel University College of Medicine in Philadelphia. Her special interests are women's health and patient education.