A Guide to Understanding Tuberculosis

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis that usually affects the lungs.  The tuberculosis bacteria is spread by infected individuals coughing and sneezing tiny droplets into the air.  Individuals infected with tuberculosis may or may not show symptoms of having the disease.



Individuals who are positive for tuberculosis fall into two different categories:  latent tuberculosis infection and active tuberculosis disease.  

Latent Tuberculosis Infection:  Most people who breathe in the tuberculosis bacteria are able to fight off the bacteria.  These individuals test positive on a PPD skin test but do not have any symptoms present.  They cannot spread the disease in the latent state.  If they do not receive treatment, however, they may develop symptoms and have the active tuberculosis disease.  Not all individuals who become infected with tuberculosis will have active tuberculosis. 

Active Tuberculosis Disease:  When tuberculosis becomes active, individuals have symptoms of the disease and can spread it to others through coughing and sneezing.  When in the hospital, these patients are on negative isolation rooms to keep the bacteria from spreading in the air to other parts of the hospital.  Symptoms of active tuberculosis include the following:

  • A bad cough lasting three weeks or longer
  • Bloody sputum
  • Pain in their chest
  • Chills 
  • Night sweats
  • Weakness or fatigue
  • Weight loss
  • Loss of appetite

Tuberculosis Risk Factors

About five to ten percent of individuals who become infected with tuberculosis will have it become the active tuberculosis disease.  These individuals have immune systems that could not keep the infection from multiplying within their bodies.  Individuals who are at a higher chance for developing the active disease commonly have illnesses which weaken the immune system.  The following are common ailments that these individuals have prior to the tuberculosis infection:

  • HIV infection
  • Diabetes
  • Severe kidney disease
  • Head and neck cancer
  • Low body weight
  • Organ transplant
  • Immunosuppressant therapy
  • Substance abuse including tobacco abuse

There are also different physical areas of work and living that put someone at risk for developing tuberculosis.  These include the following:

Working in a healthcare facility:  Working in this environment increases a person's chances of coming in contact with someone who has the active tuberculosis infection.  If you suspect that someone has active tuberculosis, they need to be in a negative airflow isolation room to keep the tuberculosis bacteria from spreading through the air.  Make sure to wear proper personal protective equipment when entering this room.  This includes a type of mask that has been fit to your face to ensure that no outside unfiltered air goes through the mask.

Working in a residential care facility:  People who live or work in prisons, nursing homes, or immigration centers. The risk is higher of contracting tuberculosis in areas with more people and poor ventilation. 

Living in a refugee camp or shelter:  These individuals are already at higher risk of developing active tuberculosis due to their weakened physical state.  When living in these areas, the risk then becomes much higher of someone spreading the disease to someone else. 


The tuberculosis PPD skin test can sometimes be wrong.  There are individuals who can react to the test who have not been infected with the tuberculosis bacteria.  If someone has very recently contracted tuberculosis, they may not react to the skin test yet.  It is important to have other tests performed to ensure that a person truly has tuberculosis.  One test that can be performed is a chest x-ray.  Another (and the true test for tuberculosis) is a blood test.  Two common names of the tests are the QuantiFERON-TB Gold in-Tube test and T-Spot Tb tests. 

After confirming that someone has tuberculosis (active or latent), medications are key to treatment.  Individuals usually take antibiotics for six to nine months.  There is a large issue with antibiotic resistance which makes it very important that individuals finish their course of treatment. If the infection becomes resistant, the course of antibiotic treatment can last 20 to 30 months. 

The most common medications used to treat tuberculosis include Isoniazid, Rifampin (Rifadin, Rimactane), Ethambutol (Myambutol), and Pyrazinamide.  For antibiotic resistant tuberculosis, many individuals receive fluoroquinolones for treatment.

Other relevant articles include:


Mayo Clinic

Centers for Disease Control

AuthorCourtney Tracy