Leprosy May Pass Between Armadillos and People
Study: Infected Armadillos, Patients Share the Same Bacterial Strain
Since the 1970s, scientists have recognized that armadillos could carry the bacteria and develop full-blown leprosy infections -- they have the lower body temperatures and longer life spans that the bacteria need to thrive, and it was suspected, based on case reports, that the animals could pass the bacteria to people.
But this new study marks the first time that an animal reservoir for the disease has ever been identified, and it means that in other parts of the world, where leprosy is much more common, animal reservoirs may be important in how the disease persists in the environment.
“Never before have we had the ability to have a biological link between organisms and cases, and now we do, which should then propel us forward being able to better deduce the risk factors that are important in transmission of the infection or that may then be perpetuating leprosy not just in the United States, but also worldwide,” Truman says.
The Risk for People
People are probably not at any greater risk than they were before, experts say.
Partly that’s because about 95% of people are genetically resistant to the infection in the first place.
“Leprosy in the U.S. is rare, and not on the rise,” says study researcher Pushpendra Singh, PhD, a scientist at Ecole Polytechnique Federale de Lausanne in Switzerland.
There are about 150 to 200 cases of leprosy reported in the U.S. each year, and about two-thirds of those, Singh says, can be traced to other countries were the disease is more common, like India and Brazil.
“However, the most possible cause of infection among the people who never left the country, or never came into the contact of any other patient of leprosy, could be the infected armadillos,” Singh says.
Some studies have shown that more than 20% of wild armadillos are infected with leprosy in some U.S. locations. Although the disease is rarely fatal to people and can be treated with antibiotics, it can kill armadillos.
In people who are infected, symptoms may not show up for three to five years, Truman says, making it tough for people to remember the circumstances that might have put them in contact with the infectious agent.
The first symptoms are generally light-colored skin lesions, which may be numb to the touch. Without treatment, the bacteria can damage nerves and lead to eventual muscle weakness, but it’s rare for most people to get to that point.
Most can be managed with antibiotics.
One big hurdle to treatment, though, appears to be that most doctors never suspect leprosy could be the diagnosis.
“You need a physician who’s willing to consider the diagnosis,” says James L. Krahenbuhl, PhD, director of the National Hansen's Disease Programs at the U.S. Department of Health and Human Services’ Health Resources and Services Administration. “There’s a need for awareness in physicians that leprosy does exist.”