ARMADILLOS AND HUMANS HAVE SOMETHING IN COMMON
by Whit Gibbons
June 26, 2005
Armadillos are literally on the move. I have recently seen reports of their becoming established in northern Missouri, Iowa, and Illinois. About ten years ago was the first time I had seen a live armadillo in central South Carolina. Maps in the most recent Peterson field guide for mammals show them nowhere near these states. Aside from their bizarre appearance and a talent for dispersal, some armadillos in Louisiana have another unusual trait. They have leprosy.
Armadillos are the only animal besides humans in which populations harbor leprosy. Leprosy, or Hansen's disease, is caused by a type of bacteria closely related to the one that causes tuberculosis. But medical researchers have yet to find a satisfactory way to culture the leprosy bacteria in the laboratory for study. Armadillos are kept in captivity at medical facilities so researchers have the bacteria on hand to test treatments and study the microorganism.
But a big mystery remains. How is leprosy transmitted? Pieces of the puzzle have been investigated by Kim Marie Tolson, a wildlife biologist at Northeast Louisiana University. As part of her research program, she and her students capture armadillos and assess them for the presence of leprosy. Leprosy has been recognized as a human affliction since biblical times, although Tolson thinks many of the references to it in the Bible were actually other skin diseases. Nonetheless, the disease still exists. Studying afflicted armadillos might provide insights into how the disease is transmitted and other aspects of its biology.
Armadillos often live more than ten years, which is important. The incubation period for the bacteria is at least two years, and possibly five or six, before it is expressed. Being long-lived is a requirement for acquiring leprosy. For example, even if possums were susceptible, their normal life span is only about two years; therefore, they would not have time to get leprosy.
Tolson's research involves catching armadillos as they scurry aboveground at her field sites in northern Louisiana. When she goes "dillering," as armadillo collecting is called, she takes several volunteers, each armed with a long-handled net. Armadillos have extraordinarily poor eyesight, making some of the chases as humorous as they are exciting. Tolson speaks of one armadillo that escaped because it ran smack into an oak tree and then turned and ran between the legs of a pursuer. Apparently, armadillos are hard to catch when you are laughing.
The captured animals, which may number as many as 60 in one day, are carried to the university where skin samples are taken and the animals are given identification marks. Samples are taken from the ears and lymph nodes, common locations of leprosy infections. The marking is done with a tattoo press, each animal receiving its personal ID on the inside of the shell-like outer covering. Animals are released at their site of capture within 72 hours, with the researchers hoping to recapture them later.
One-fourth of the armadillos captured in Tolson's study have identifiable leprosy. Others may have been exposed but are carriers only or have not yet manifested the symptoms. Humans generally show signs of leprosy through deterioration of the extremities. Armadillos seem to have a bigger problem: the disease is usually fatal. Tolson has even discovered leprosy infections in the bone marrow. These funny-looking mammals are indeed completely susceptible to the disease throughout their systems. However, most of them lose their lives on highways, as armadillos, like possums, are seriously road-challenged.
One point Tolson makes about the ecology of leprosy in armadillos is that most of the infected animals come from bottomland hardwood forests rather than from more open, drier habitats. Also, virtually all reported cases of leprosy in armadillos have been west of the Mississippi River, hence not in Florida where the largest eastern populations occur, and as far as is known, not in the many new areas armadillos are moving into. Incidentally, few if any humans have ever been known to contract leprosy from the Louisiana armadillos.
Although Hansen's disease does not have the social stigma associated with it in earlier times and can usually be controlled with medication in humans, it's nice to know we have the armadillo as a partner for studying it.If you have an environmental question or comment, email
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FAQs
ARMADILLOS AND HUMANS HAVE SOMETHING IN COMMON? ›
They have leprosy. Armadillos are the only animal besides humans in which populations harbor leprosy. Leprosy, or Hansen's disease, is caused by a type of bacteria closely related to the one that causes tuberculosis.
What do humans and armadillos have in common? ›What do armadillos and humans have in common? They can both be infected with leprosy, one of the oldest and most dreaded diseases known to man. In fact, without this unusual mammal from the Americas very little progress would have been made in the search for a treatment for the disfiguring disease.
What do humans use armadillos for? ›Because of the armadillo, scientists have been able to develop a vaccine against leprosy. The nine-banded armadillo has become the principal source of M. leprae in biochemical and immunological research.
What are armadillos associated with? ›Armadillos are often used in the study of leprosy, since they, along with mangabey monkeys, rabbits, and mice (on their footpads), are among the few known species that can contract the disease systemically.
What animal still carries leprosy? ›Nine-banded armadillos are the only mammals other than humans that have been shown to carry Mycobacterium leprae, or M. leprae, the bacteria that causes leprosy.
What is the closest animal to a armadillo? ›Description: Its closest relative is the anteater, which has a similar shape; long tail and snout. Heavily armored, the only exposed skin is on the under belly, which is protected when the animal curls into a tight ball (when threatened).
How many babies do armadillos have? ›Four young are born in a burrow in March. All four young, always of the same sex, are identical quadruplets and developed from the same egg. They even share a single placenta while in the womb. Armadillos are the only mammals in which multiple young form from a single egg with any regularity.
What is a nickname for armadillos? ›The unusual looking armadillo is known by several nicknames: Possum on the half-shell. Armored pig. Rolling armored ball.
Are armadillos mean or aggressive? ›Although the armadillo is not aggressive, it is a wild animal that can potentially spread disease to humans if handled or eaten. As with any wild animal, armadillos can transmit rabies, although this is very rare.
Are armadillos friendly to humans? ›Armadillos are passive creatures and, unless cornered, are very unlike to show any aggression towards humans. They only eat worms and small insects, so there is zero chance of one attacking out of hunger or just randomly.
Do armadillos have teeth? ›
Armadillos lack canines and incisors; they have uniform continuously growing peg-like cheek teeth (premolars and molars) which lack enamel. The teeth have open roots that allow for continuous growth. The peg-like teeth are used to mash up their food.
How long do armadillos live? ›Nine-banded armadillos typically live from 7 to 20 years in the wild. One captive armadillo lived 23 years. Populations of nine-banded armadillos are increasing. Humans have killed off most of their natural predators, and roadways have offered them easier means of travel to new habitats.
Did armadillos go extinct? ›Giant armadillos are listed as 'Vulnerable to Extinction' by the IUCN, are rare throughout their range, and have experienced local extinctions in Uruguay and elsewhere. While habitat destruction, poisoning, and hunting pose major threats to remaining populations, much about this species remains unknown.
Do armadillos lay eggs? ›Armadillos do not lay eggs. They are mammals and give birth to live young.
Are armadillos harmless to humans? ›Are Armadillos Dangerous to Humans? Because the pests are docile and frighten easily, armadillos are not dangerous to humans. However, these animals may cause problems by digging near foundations or damaging gardens.
Will armadillos approach humans? ›They don't usually bite or attack humans and pets but it's always a possibility especially when armadillos feel threatened. Just because you won't get bitten or scratched doesn't mean it's safe to have armadillos around.