The nine-banded armadillo (Dasypus novemcinctus) is a distinctive mammal recognizable by its bony, armored shell. Its range has expanded significantly across the United States, moving from the deep South into northern and eastern regions. Because this unique animal lives in close proximity to human habitats, concerns often arise regarding the potential for disease transmission from these burrowing creatures. Understanding the specific health risks associated with the armadillo requires examining the few pathogens they can carry, particularly one that has a unique biological connection to the species.
The Unique Link to Hansen’s Disease
Armadillos are one of the only non-human animals that can naturally harbor Mycobacterium leprae, the bacterium responsible for Hansen’s disease (leprosy). This unusual biological link is attributed to the armadillo’s naturally low core body temperature, approximately 90 degrees Fahrenheit (34 degrees Celsius). This temperature provides an ideal environment for M. leprae to thrive, making the armadillo a natural reservoir for the pathogen.
The link between armadillos and human cases was confirmed by genetic sequencing, which showed that the strain of M. leprae in armadillo populations matched the strain found in human patients in the same region. This confirms the possibility of zoonotic transmission (animal-to-human spread). The primary risk of infection occurs through direct contact with an infected animal, such as handling a live or deceased armadillo, or exposure to its tissues and blood.
While armadillos can carry the bacteria, the overall risk of contracting Hansen’s disease from them remains extremely low for the general public. Only about 150 to 250 new cases are reported in the United States each year, and the majority are acquired during international travel. A small percentage of cases, however, are linked to armadillo exposure in southern states like Texas, Louisiana, and Florida, where the animal population has a higher prevalence of infection. Up to 20% of armadillos in some populations may carry the bacteria, but the vast majority of humans are naturally resistant to the disease.
Other Potential Zoonotic Pathogens
Beyond the unique risk of Hansen’s disease, armadillos can also carry other pathogens common to many wild animals, primarily through environmental contamination. The most widely recognized of these is Salmonella, which causes gastrointestinal illness in humans. Transmission typically occurs through contact with armadillo feces, which can contaminate soil, water, or surfaces.
The infection risk increases in areas where armadillos are actively digging and defecating, potentially tracking the bacteria into residential spaces. Symptoms of salmonellosis usually include diarrhea, fever, and abdominal cramps. While often mild, the infection can become serious in young children, the elderly, or those with compromised immune systems. The risk of exposure to this bacterium is not unique to armadillos, as many reptiles and mammals can carry and shed Salmonella.
Armadillos are also a natural reservoir for the parasite Trypanosoma cruzi, which causes Chagas disease. This parasite is primarily transmitted to humans by the triatomine bug, or “kissing bug.” The armadillo hosts the parasite, contributing to its prevalence in the environment and the potential for the insect vector to become infected. Other possible infections include the fungal agent causing histoplasmosis, found in contaminated soil near droppings, and tapeworms, which are parasitic organisms whose eggs can be shed in feces.
Reducing Risk Through Safe Interaction
The most effective strategy for preventing disease transmission from armadillos is to minimize direct contact with the animals and their environment. Avoid touching or handling any armadillo, whether alive or deceased. Even dead animals can harbor pathogens, and exposure to blood or tissue during handling presents a risk.
When working outdoors in areas where armadillos forage or burrow, such as gardening, wearing protective gloves is a practical precaution. Gloves help prevent pathogens in the soil, such as Salmonella or fungal spores, from entering the body through cuts or abrasions. Additionally, keep children and pets from approaching armadillos or disturbing their burrows to reduce potential exposure.
For individuals who consume armadillo meat, it is recommended to cook the meat thoroughly until it reaches a safe internal temperature. High heat effectively kills any M. leprae or Salmonella bacteria that may be present, drastically reducing the risk of infection. Basic hygiene practices, such as washing hands thoroughly with soap and water after any outdoor activity, especially after gardening or contact with soil, are essential defenses against zoonotic transmission.