Armadillos, particularly the nine-banded species (Dasypus novemcinctus), are North American mammals that serve as reservoirs for several human pathogens. A zoonotic disease is transmissible from animals to humans, and armadillos are one of the few non-human species confirmed to harbor these agents. Their physiology includes a lower core body temperature, fluctuating between 32 and 36 degrees Celsius, which creates a permissive environment for specific bacteria. This lower temperature makes them susceptible to pathogens that cannot survive the higher internal temperatures of most other mammals. Understanding the risks associated with these animals is important for safe coexistence.
Armadillos and Hansen’s Disease
The most recognized pathogen associated with armadillos is Mycobacterium leprae, the bacterium responsible for Hansen’s disease (leprosy). Armadillos are the only non-human animal naturally infected with this bacterium in the United States, acting as a wildlife reservoir. This link exists because their low body temperature closely mimics the 27 to 33 degrees Celsius required for the slow-growing organism to thrive. This temperature range is similar to the cooler extremities of the human body where the bacteria often proliferate.
Transmission to humans typically involves prolonged, close interaction with an infected animal, rather than casual contact. This includes handling, skinning, or cleaning a live or dead armadillo. Consumption of undercooked armadillo meat is another potential route of exposure in regions where this practice occurs. Although the risk remains low, most domestically acquired cases of Hansen’s disease in the southern U.S. have been genetically linked to strains found in wild armadillos.
The risk is concentrated in the Southern U.S., particularly in states like Texas, Louisiana, Florida, and Mississippi, where armadillo populations are high. Scientists estimate that 15% to 20% of the wild armadillo population in some endemic areas may carry the bacteria. Awareness of this zoonotic link is important for individuals who live in or travel through these regions and frequently encounter the animals.
Other Bacterial and Protozoan Pathogens
Armadillos can harbor other pathogens, notably the bacterium Salmonella, which poses a risk through environmental contamination. They carry Salmonella in their digestive tracts and shed it through their feces, contaminating surface water and soil. This introduces a risk of infection if contaminated garden produce or water sources are ingested. Since the bacteria can persist in the environment, exposure can occur through droppings without direct contact with the animal.
Armadillos also act as a reservoir for the protozoan parasite Trypanosoma cruzi, the agent that causes Chagas disease. The parasite circulates among wild animals like armadillos, opossums, and raccoons in a sylvatic cycle. The armadillo does not directly transmit the disease to humans. Transmission occurs through the bite of an infected triatomine bug, often called a “kissing bug,” which acquires the parasite from the armadillo. The bug defecates near the bite site, and the parasite enters the human host when the fecal matter is rubbed into a wound or mucous membrane.
Indirect Environmental Fungal Risks
Health concerns related to armadillos involve environmental fungi, particularly Histoplasma capsulatum, which causes the respiratory infection Histoplasmosis. This fungus thrives in soil enriched with the droppings of various animals, including bats and birds. Armadillos frequently disturb the soil layers where these fungal spores are concentrated due to their strong claws and burrowing activity.
The risk to humans stems from the environmental disturbance caused by the armadillo, not from the animal being sick. When an armadillo digs or creates a new burrow, it aerosolizes the microscopic fungal spores into the air. Inhalation of these spores, known as microconidia, is the route of infection, typically affecting the lungs first. Individuals who clean burrows or work in areas with armadillo activity should be aware that disturbing the soil can release these airborne particles.
Minimizing Exposure and Safe Coexistence
The most effective way to prevent exposure to armadillo-borne pathogens is to maintain a safe distance and never touch or handle the animals. Since armadillos forage primarily for insects and grubs, property owners can limit their presence by controlling these food sources. Applying beneficial nematodes or appropriate soil insecticides can reduce the grub population that attracts them.
Exclusionary tactics are necessary to keep armadillos from digging and creating burrows near human dwellings. Because of their digging ability, a simple fence is ineffective. Barriers should extend at least 12 inches high above ground and be buried 12 to 18 inches deep, sometimes with an outward slant. Removing potential shelter like brush piles and reducing lawn moisture also makes the environment less appealing.
If cleanup of a burrow or area with armadillo droppings is required, specific safety protocols should be followed to minimize the risk of spore or bacterial inhalation. Individuals should wear protective gear, including gloves and a properly fitted mask. They should dampen the affected soil with water before disturbing it, as this process helps prevent the aerosolization of fungal spores and other contaminants.