Armadillos, Leprosy, and... You?

The lovable armored creature that is the armadillo carries with it leprosy, a disease stigmatized by mankind throughout history. Can humans actually contract leprosy from a these tank-like wonders of nature?

Armadillos, Leprosy, and... You?

Leprosy Under Their Shells
Not all armadillos actively carry Mycobacterium leprae, the bacteria leading to the ancient affliction of leprosy. Only the nine-banded armadillo, a species common in the southeastern United States, is known to act as a carrier.

Leprosy is an uncommon disease in North America that brings with it an ancient stigma of biblical proportions. The ability for an armadillo to carry leprosy is not all bad, as it provides scientists with a easy to handle host organism for studies of the disease.

Although leprosy can lead to permanent damage of the extremities, most cases are easily halted with modern medicine, thus saving the afflicted from an extended stay at a leper colony.

But why would armadillos carry leprosy? That's a darn good question.

Low Body Temperature and Bacteria
It is hypothesized that this species of armadillo is able to carry Mycobacterium leprae due to their low body temperature. The animal's internal body temperature hovers around 90°F. M. leprae is particularly difficult to grow in laboratory conditions, which often replicate room temperature or human body temperature.

This intermediate temperature — not too hot, not too cold — present within armadillos allows for M. leprae to thrive, but exactly how an armadillo becomes exposed to the bacterium is unknown. Armadillo to armadillo exposure is an obvious route for modern bacterial transmission amongst the animals, but at some point the bacteria likely crossed species.

Armadillos, Leprosy, and... You?

Shuffling Down the Interstate
As a denizen of the southeast, seeing deceased armadillos along the road is a common sight that accompanies any out of state road trip. Bodies of the creatures litter the gutters of the interstate, and, it appears that a very, very small number of citizens of the Southeastern United States look to the nine-banded armadillo as a plaything and a food source.

A connection between leprosy and human contact armadillos has been suggested for decades, but only in the past two years has extensive research been carried out to look for a transmission connection.

A 2011 retrospective study looked at 25 infected humans living within in the United States. All 25 carried leprosy derived from Mycobacterium leprae. Of the 25 individuals, 15 handled armadillos regularly or consumed armadillo flesh. I'm not sure where armadillos lie on the food pyramid, but I would advise you to shuffle the creatures toward the bottom.

Armadillos, Leprosy, and... You?

Do Armadillos Spread Leprosy to Humans?
Although nine-banded armadillos freely roaming the Southeastern United States can carry leprosy, they are not the critical choke point for the spread of Mycobacterium leprae.

The overwhelming majority of human cases are derived from contact with human carriers while traveling to parts of the world where humans are routinely infected with leprosy.

Of the approximately 150 human cases that arise in the United States each year, nearly 80% of these cases stem from human to human transmission during travels overseas.

But don't worry — if you are an armadillo aficionado showing the tell-tale skin lesions of leprosy, you will not be taken away from your family and sent to a leper colony. If discovered early, a full course of antibiotics can treat most cases and forgo nerve damage and physical impairment, with additional medication given to control inflammation.

The World Health Organization currently provides multidrug therapy for free to all individuals afflicted with leprosy in countries where person to person transmission is an issue. It is likely that by the end of the 21st Century, the nine-banded armadillo will the last carrier of this ancient scourge on the planet.

Top image via Tambako the Jaguar/Flickr. Additonal images via Chris Caldwell/Flickr, Diane Turner/Flickr, and alh1/Flickr.