A leprosy outbreak in Florida is being attributed to an unlikely source: armadillos. Nine cases of the disease have been reported thus far in 2015—almost double the usual state rate, which sees an average of 10 diagnoses per year—with the most recent victim citing exposure to the New World mammals.

The illness, which is clinically termed Hansen’s Disease, infects approximately 100 U.S. citizens annually. While best known as an affliction rife during biblical times, it is now most common in Southern states including Texas and Louisiana. “It’s a surprise to most people that leprosy is still in the United States,” says Dr. Leisha Nolen, an epidemic intelligence service officer at the Centers for Disease Control and Prevention (CDC). “Doctors should be aware that leprosy is still present [here]. It’s rare…but it would be tragic if they miss it.”

Leprosy is caused by mycobacterium laprae, a slow-growing bacillus, and can be transmitted via droplets from the nose and mouth of people with severe, untreated cases of the disease. The glacial rate of growth of the bacteria means that symptoms may not materialize anywhere from four to 20 years after the disease has been contracted. “Most people think you can’t do anything about it, but leprosy is a disease that’s treatable with antibiotics,” Dr. Nolen explains. Without treatment, it can cause nerve damage, muscle weakness, and permanent disabilities, though the centuries-old images of atrophying body parts are thought to no longer be a likely risk afflicting present-day sufferers.

The first connections between the disease and armadillos were established in a 2011 paper entitled “Problematic Zoonotic Leprosy in the Southern United States.” Genome resequencing of three U.S. patients with leprosy and a nine-banded armadillo found the infective strains to be almost identical, proving that zoonosis—diseases that can be passed from animals to humans—was at play. The CDC estimates that more than 60 percent of infectious human diseases originate from animals, and this process is the cause of major illnesses including malaria, Ebola, and tuberculosis.

Armadillos are believed to be the only animal able to carry leprosy—which some scientists believe they contracted from humans hundreds of years ago—and are common across Florida. “We catch more armadillos than we do any other species,” wildlife trapper Kyle Waltz told Action News Jacksonville. “If they’re trying to get out of a cage they can spit on you.” Residents have raised concerns that the critters may bite domestic pets, resulting in bacterial infections akin to those transmitted by rodent bites.

A new case reported in Flagler County, Florida, is the first to be declared there for at least 15 years, which has led to fears that contact with the creatures may see infection rates rise even further. Armadillos are sometimes shot and eaten by locals, and infections may be growing in number due to humans encroaching on the animals’ habitat. Medical experts are assuring residents that ceasing any kind of interaction with them should alleviate the risk of disease contraction.