While bacteria can live pretty much everywhere, Mycobacterium leprae has a pretty standard habitat. It was thought for many years that humans were the only organisms able to carry Leprosy. It wasn't until the 1960's when scientists began looking at the characteristics of mycobacterium that they thought to test out armadillos. Armadillos had the characteristics of an organism capable of contracting the disease because this bacteria lives in cold parts of the body, (hands, feet, nose, etc.) and armadillos have a fairly low body temperature compared to most other mammals. They also have long lives, between 12-15 years, which works well with the slow progression of this disease. Armadillos and humans are still the only known organisms capable of contracting Mycobacterium leprae. Because this bacteria is unable to be grown on artificial mediums, armadillos are often used. The foot beds of the armadillos are used to grow the bacteria. People can then use this information to test lesions on the body of suspected leprosy patients to see if they are indeed leprosy victims.
Also note, that while armadillos are used in the lab, it has been found that some armadillos have naturally contracted the disease without any human involvement. Humans working with armadillos at a zoo, for example, don't need to worry too much about contracting the disease from a armadillo. This is due to the rather small chance the animal has the disease. Only about 5% of armadillos naturally contract the disease, and 95% of humans have a natural immunity towards leprosy. Because of this, the chances are slim.
Mycobacterium leprae are also non-motile bacteria. Once they get ingested into the body they are basically "floating" around.
Find out what M. leprae looks like!
Created by Alicia Jaedike
Last updated: April 2008