Nine-banded armadillos, common in the southern United States, can carry the bacterium Mycobacterium leprae, which is the cause of leprosy. While this connection is a documented scientific phenomenon, human infection from armadillos remains uncommon. Despite the presence of the bacteria in these animals, the overall risk of contracting leprosy from them is considered low.
Why Armadillos Can Carry Leprosy
Armadillos are susceptible to Mycobacterium leprae due to their unusually low body temperature. Their average body temperature, approximately 32 to 35 degrees Celsius (89 to 95 degrees Fahrenheit), is ideal for M. leprae growth and survival, as the bacterium thrives in cooler environments. This physiological trait allows the bacterium to multiply effectively throughout the armadillo’s body, including internal organs, skin, and nerves. Armadillos are one of the few non-human animals known to naturally harbor M. leprae, making them a significant natural reservoir for the disease. In some areas, studies indicate that 15 to 20% of armadillo populations may carry the bacteria.
How Humans Can Contract It
Human contraction of Mycobacterium leprae from armadillos primarily occurs through direct and prolonged contact with infected animals, including handling live or dead armadillos, skinning them, or consuming their meat. While the exact route of transmission is not fully understood, bacteria are believed to enter the human body through breaks in the skin from contact with infected fluids or tissues. Geographically, this transmission is most likely to occur in states with large armadillo populations and historical leprosy cases linked to these animals, such as Texas, Louisiana, Florida, Mississippi, and Arkansas. There is also ongoing research into the possibility of soil contamination, where armadillos may shed the bacteria through burrowing and defecating, potentially infecting humans who handle contaminated soil. Despite these potential routes, human cases of leprosy linked to armadillos are rare.
Minimizing Exposure Risk
To reduce the risk of exposure to Mycobacterium leprae from armadillos, avoid direct contact with these animals, including refraining from touching, handling, or approaching wild armadillos, particularly those that appear sick or are found dead. Hunting, skinning, or consuming armadillo meat should also be avoided, as these activities increase the likelihood of direct exposure to the bacteria. If contact with an armadillo or its environment is unavoidable, such as when moving an animal from a property or working in areas where armadillos are known to burrow, wearing sturdy gloves is recommended. Practicing good hygiene, including thorough handwashing with soap and water after any potential contact with wildlife or soil where armadillos may have been active, further helps to minimize risk. Implementing measures like fencing can also help deter armadillos from entering residential areas.