Tuberculosis (TB)

A vaccine preventable disease

Identification and Definition

Tuberculosis, or TB, is a disease caused by the Mycobacterium tuberculosis bacterium and can be fatal if left untreated. TB is spread through the air and not everyone who is infected becomes sick. While not commonly used in the United States, the Bacille Calmette-Guerin (BCG) is the vaccine used in other countries where TB is more common.

History of Tuberculosis

The Mycobacterium tuberculosis bacterium has existed for 15,000 to 20,000 and been found in relics in ancient Egypt, India, and China. TB has gone by other names such as consumption, phthisis pulmonaris and the white plague. Today, as much as 1/3 of the world's population has been exposed and is infected. In developing countries as much as 90% of people are exposed and infected. In 2014 the incidence rate was 3.0 cases per 100,000 person with a total of 9,412 new cases reported.

Originally there was a surgical treatment for tuberculosis that was common and found to prolong life. It involved draining pleural effusion from around the lungs. In 1921 the BCG vaccine was introduced thanks to Albert Calmette and Camille Guerin.

Signs and Symptoms of Tuberculosis

Symptoms of pulmonary TB (TB in the lungs) include:

  • Cough that lasts 3+ weeks
  • Pain in your chest
  • Coughing up blood

While other symptoms include

  • Weakness or fatigue
  • Weight Loss
  • Loss of appetite
  • Chills
  • Fever
  • Night sweats

People with latent TB infections do not feel sick, don't show any symptoms, and cannot spread TB to others.


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Transmission of Tuberculosis

Mycobacterium tuberculosis is carried in air borne particles that may remain in the air for several hours. Transmission happens when a person inhales these air borne particles and the bacterium travels to the lungs. Susceptibility of the healthy person, infectiousness of the infected person, environment, and exposure (proximity, frequency, and duration) all play a role in the probability of transmission.

Mycobacterium bovis is the bacterium responsible for tuberculosis in cattle but it can also infect humans and other mammals. Mycobacterium bovis is usually transmitted to human through infected milk but it is rare due to pasteurisation. In a areas where pasteurisation is not routine, Mycobacterium bovis is a more common cause of tuberculosis in humans.

Complications of Tuberculosis

Typically tuberculosis affects the lungs but the disease can be spread throughout the body via the bloodstream. Possible complications include:

  • Spinal pain - back pain and stiffness
  • Joint damage - arthritis usually in the hips and knees
  • Meningitis - can cause a lasting or intermittent headache.
  • Liver or kidney problems
  • Heart disorders - rare but tb can infect the tissue surrounding your heart causing inflammation and fluid collections. This is called cardiac tamponade which may be fatal
  • Death - if left untreated, tuberculosis kills more than 50% of people infected


Recommended Control Measures for Tuberculosis

While tuberculosis is very contagious there are just a few easy recommended measures to stop possible transmission including the BCG vaccine (in areas with large numbers of tuberculosis) and leading a healthy, active lifestyle.
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