Crossposted from Healthland:
It can sometimes seem that we spend most of our journalistic time trying to scare you. Or maybe that’s just my posts — I tend to get the environmental danger of the week. But, sorry to say, I’ve got another thing for you to be frightened of, and it’s something you might not expect: armadillos.
That’s right, armadillos — the armored placenta mammal found throughout much of the South. You probably imagined that, at worst, the threat posed by armadillos would be to your car by becoming roadkill, but that’s not all. According to a new study in the New England Journal of Medicine, armadillos may actually be spreading leprosy to human beings. “There is a very strong association between the geographic location of the presence of this particular strain of M. leprae [a strain of the bacteria that causes leprosy] and the presence of armadillos in the Southern U.S.,” said Stewart Cole, the head of the Global Health Institute at EPFL in Switzerland and a lead author on the paper. “Our research provides clear DNA evidence that the unique strain found in armadillos is the same as the one in certain humans.”
A little background first: armadillos are one of the few animals, aside from human beings, that carry the leprosy-causing bacteria. The disease itself — which is characterized by disfiguring skin sores and nerve damage — is extremely rare in the U.S., with about 150 cases diagnosed annually. Most Americans who contract leprosy have worked in areas overseas where leprosy is endemic, such as parts of Brazil, the Congo and India; these cases are considered imported.
But, then, health authorities found that up to one-third of U.S. cases appeared to have been contracted in country — even in victims who didn’t seem to have had any contact with a human leprosy patient. These cases were most common in the states of Texas and Louisiana, but the range is now slowly expanding. Armadillos — almost by process of elimination — were suspected, but there was no solid evidence.
The NEJM researchers — from the Global Health Institute and Louisiana State University — drew up a study that included 33 wild armadillos known to have the disease, and 50 leprosy patients. They found a new strain of M. leprae, called 3I, in 28 armadillos and 22 patients who had never been abroad (and thus could not have contracted the disease from other people with leprosy). After sequencing the new strain and comparing it to other known strains from around the world, the researchers concluded that the leprosy patients and the infected armadillos had the same strain. The fact that eight of the patients recalled having contact with armadillos, including one who frequently hunted and cooked the animals for meat, only bolstered the researchers’ confidence.
Overall, the NEJM study shows that the chance of contracting leprosy from an armadillo is quite remote, even if you do have direct contact with one. But the researchers caution that people should be discouraged from hunting, cooking and eating armadillo meat, to prevent even the chance of spreading leprosy (though it’s important to remember that leprosy sufferers can now be treating with a range of antibacterials). Just in case, though, cut out the armadillo steak.