Etiological agent = Mycobacterium spp. (gram [+], acid-fast rods)

Tuberculosis (TB) is a disease of great historical significance in both humans and domestic animals, but it is by no means gone. TB IS STILL ENDEMIC/ENZOOTIC THROUGHOUT LARGE REGIONS OF THE WORLD. ONE OUT OF EVERY 3 PEOPLE IN THE WORLD (2 BILLION PEOPLE!) ARE ESTIMATED TO BE INFECTED AND IT REMAINS THE MOST COMMON INFECTIOUS CAUSE OF DEATH AMONG ADULTS, KILLING 2-3 MILLION PEOPLE EACH YEAR. Most recently, the incidence of TB has undergone a dramatic resurgence, even in developed countries, due to the occurrence of TB in AIDS patients and the development of multi-drug resistant Mycobacterium strains. In 1994 for instance, there were 24,000 cases of TB among people in the U.S.

To understand the etiology of TB, it is critical to realize that there are multiple strains of Mycobacterium spp., each with its own primary reservoir species. The major strains of interest are:

• Mycobacterium tuberculosis is the classic cause of human TB and human beings are its primary reservoir.
• Mycobacterium bovis is the classic cause of bovine TB and cattle are its major reservoir, although it is zoonotic to humans.
• Mycobacterium avium (aka the "M. avium intracellulare complex" of mycobacteria) are a group of organisms that are found ubiquitously in the environment (soil/water) and can infect and cause disease in humans and both domestic and wild animals.
  

Tuberculosis topics

(To view any of these topics, simply click on the appropriate subject.)

• Mycobacterium tuberculosis
• Mycobacterium bovis
• Mycobacterium avium
• Mycobacterium marinum, M. genavense, M. kansasii, M. fortuitum and M. phlei
• References

First Tuberculosis topic