Armadillos are distinctive mammals, recognized by their unique, leathery armor shells. These creatures play a role in various ecosystems across the Americas, primarily known for their digging habits. Like many wild animals, armadillos can carry pathogens, raising questions about potential health considerations for humans. Understanding the general concept of zoonotic diseases, which are diseases transmissible from animals to humans, is important when considering interactions with wildlife.
Leprosy and Armadillos
Hansen’s Disease, commonly known as leprosy, is the primary health concern associated with armadillos. This chronic infectious disease is caused by the bacterium Mycobacterium leprae. Armadillos are notably unique in their susceptibility to this bacterium, as they are one of the few non-human animals known to naturally harbor M. leprae. Their suitability as hosts stems from their unusually low average body temperature, which typically ranges from 33 to 36 degrees Celsius (91 to 97 degrees Fahrenheit). This cooler internal environment provides an ideal condition for Mycobacterium leprae to thrive, as the bacterium prefers temperatures lower than the core body temperature of most mammals.
The nine-banded armadillo (Dasypus novemcinctus) is the species primarily implicated in carrying the leprosy bacterium. High prevalence rates of M. leprae in armadillo populations have been observed in the Southern United States, including states like Texas, Louisiana, Florida, Mississippi, Alabama, and Georgia. Studies indicate that the infection rate can exceed 16% to 20% in armadillos within some of these regions. Estimates suggest that over 100,000 armadillos in states such as Texas and Louisiana carry the bacteria.
Understanding Transmission
Transmission of Mycobacterium leprae from armadillos to humans is a known, though uncommon, occurrence. The primary pathways for this zoonotic transmission involve direct contact with infected armadillos, handling their carcasses, or consuming undercooked armadillo meat. Specific instances of human exposure have been linked to contact with the blood and tissue of infected animals.
Globally, human-to-human transmission of leprosy is significantly more common than armadillo-to-human cases. The bacterium typically spreads between people through prolonged, close contact, often via respiratory droplets from an untreated individual. It is important to note that most people possess a natural immunity to Mycobacterium leprae, with approximately 95% of the population not developing the disease even after exposure. In the United States, cases of leprosy transmitted from armadillos are rare, accounting for a small fraction of the 150 to 250 new cases reported annually, many of which are associated with international travel.
Minimizing Risk
To reduce the risk of contracting diseases from armadillos, particularly leprosy, several practical precautions are advisable. It is best to avoid direct contact with armadillos altogether, refraining from handling them or attempting to keep them as pets. If contact becomes unavoidable, such as during a rescue situation, wearing protective gloves is recommended.
For individuals who might consume armadillo meat, ensuring it is thoroughly cooked is a crucial step to eliminate potential pathogens. Maintaining good personal hygiene after any potential exposure to armadillos or their habitats is also important, which includes washing hands thoroughly. These measures collectively help to minimize the chances of disease transmission from armadillos to humans.
Other Health Considerations
Beyond leprosy, armadillos can potentially carry other pathogens, though these are generally considered less significant concerns for the general public. These include:
Salmonella bacteria, which armadillos can carry in their digestive tracts and shed in their feces. Transmission can occur through contact with contaminated soil, water, or food, leading to symptoms like diarrhea, fever, and vomiting.
Armadillos may also host parasites such as tapeworms, which can be transmitted through contact with or ingestion of contaminated feces.
While rare, armadillos can also be affected by rabies, a serious viral disease typically transmitted through bites or scratches. Observing unusual behavior in an armadillo, such as a lack of fear of humans or daytime activity, might indicate illness.
Other less common risks include fungal infections like histoplasmosis, acquired from spores in feces-contaminated soil, and bacterial infections like leptospirosis, spread through urine.