Americans who contracted leprosy in the United States did so after direct contact with armadillos, an international team of researchers said.
Researchers at the Global Health Institute at EPFL in Lausanne, Switzerland, and Louisiana State University say there is clear evidence that a never-before-seen strain of Mycobacterium leprae emerged in the Southern United States and it can be transmitted via infected armadillos.
Stewart Cole, head of the Global Health Institute, says it has been known since the 1970s that armadillos are potential carriers of the disease -- most likely introduced by European immigrants 500 years ago.
"There is a very strong association between the geographic location of the presence of this particular strain of M. leprae and the presence of armadillos in the Southern United States," Cole says in a statement. "Our research provides clear DNA evidence that the unique strain found in armadillos is the same as the one in certain humans."
There are about 150 cases of leprosy in the United States each year, mostly contracted by people who have been abroad where leprosy is endemic, but health authorities found one-third of these patients were infected, but had not left the country.
The scientists confirmed by DNA analysis that 28 wild armadillos and 22 leprosy patients all had the same strain of the leprosy bacteria.
The study is published in the New England Journal of Medicine.