Although rare, leprosy, an infectious disease that attacks the skin and nervous system could be making a comeback in Florida.
In 2020, 159 new cases of leprosy were reported in the United States, with Central Florida accounting for nearly one-fifth of the infections, according to a recent report from the CDC.
Carl Abraham, M.D., infectious disease physician and assistant professor at the New York Institute of Technology College of Osteopathic Medicine, says that leprosy infections in the U.S. are usually linked to immigration from other countries where the disease is more widespread.
While the drivers of the current increase in leprosy cases in Florida are unknown, the outbreak can be caused by changes in migration patterns of people or the armadillo, the only other animal that can be infected by Mycobacterium leprae, the leprosy-causing bacteria. Abraham says that these barrel-shaped animals are the suspected source of most local human cases.
Changes in the insect populations on which the armadillo feeds or genetic mutations of M. leprae that could make it more contagious to humans could have also played a role in raising the number of cases.
Abraham says that "it is very possible" that the current outbreak of leprosy in Florida becomes an epidemic, meaning the number of cases would increase even further. However, an epidemic could be prevented by allocating enough resources to determine the outbreak's source, educating the community, including healthcare providers, and finding and treating patients with both symptomatic and asymptomatic infections.
Leprosy is more contagious armadillo-to-armadillo and armadillo-to-human than it is human-to-human, Abraham says. M. leprae thrives at temperatures of 90 to 94°F, which is the body temperature of the armadillo, and as much as 20% of the armadillo population in the U.S. is infected.
"Exactly how easy it is for a person to be infected by an armadillo is not known. Once infected, M. leprae does not grow as well in human tissues unless the person has a defect in the immune system. Human-to-human transmission is estimated to require months or years of frequent exposure," he says.
Nevertheless, Abraham says that leprosy in the U.S. is still rare, and most people don't need to be concerned about it. The best way to prevent leprosy is to avoid armadillos, specifically 9-banded armadillos, commonly found in the southern U.S. from New Mexico to Florida to West Virginia.
He says that if you notice dirt mounds or holes the size of the football that armadillos may have caused, you should contact your local fish and wildlife department to get information on how to remove them.
"Most importantly, do not approach or touch an armadillo in the wild, either dead or alive, as even manipulation of dead armadillo tissue may cause M. leprae bacteria to be airborne and breathed into the lungs, thus setting up an infection."- Abraham
Leprosy is easily treatable with antibiotics, especially at early stages, and those who complete treatment are almost always cured, Abraham says. However, the difficulty is recognizing the illness, as most people in the U.S., including healthcare providers, have never seen a case.
Abraham explains that in humans, M. leprae infects the skin and nerves closest to the skin because these tissues are usually a few degrees colder than our core temperature of 98.6°F.
"Any person with one or multiple patches of skin that are lightening in color and have decreased sensation (for example, numbness) should be tested for infection with M. leprae. The patch may be flat or raised," he adds.
Abraham warns that it may take a year or more for those infected to develop symptoms. When left untreated over many years, leprosy can result in ulcers (wounds) on the bottoms of the feet and severe disfigurement that results in paralysis and crippling of the hands and feet.