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“Contrary to historical beliefs, leprosy is not highly contagious,” Dr. Lucar, an infectious disease physician and associate professor of medicine at George Washington University, Washington, said in an interview. “For reasons that have to do with the makeup of genes that affect their immune system, most people are not susceptible to acquire leprosy. It’s really a small percentage of the population. It does require prolonged contact with someone with untreated leprosy – over several months – to acquire an infection. So, the risk from any type of casual contact is low.”
According to apublished in the CDC’s Emerging Infectious Diseases, the number of reported leprosy cases has more than doubled in the past decade. Of the 159 new cases reported nationwide in 2020, Florida accounted for about one-fifth of cases, with most limited to the central part of the state. “In the U.S., there have been 150-250 cases reported each year over the past several years,” said Dr. Lucar, who was not affiliated with the research letter. “What seems to have changed is that since 2015, there has been a rise in cases in people who are U.S.-born “In the U.S., there have been 150-250 cases reported each year over the past several years,” said Dr. Lucar, who was not affiliated with the research letter. “What seems to have changed is that since 2015, there has been a rise in cases in people who are U.S.-born," and currently, about one-third of leprosy cases are in individuals born in the United States, he noted.
The research letter described a case of leprosy in a 54-year-old man who worked in landscaping, who sought treatment at a dermatology clinic in Central Florida in 2022 for a painful and progressive erythematous rash. The lesions began on his distal extensor extremities and progressed to involve his trunk and face. According to the report, the man denied any domestic or foreign travel, exposure to armadillos (a known source of transmission), prolonged contact with immigrants from leprosy-endemic countries, or connections with someone known to have leprosy. The authors concluded that the case “adds to the growing body of literature suggesting that central Florida represents an endemic location for leprosy. Travel to this area, even in the absence of other risk factors, should prompt consideration of leprosy in the appropriate clinical context.”
Dr. Lucar said that the mechanism of leprosy transmission is not fully understood, but armadillos, which typically traverse the southern United States, are naturally infected with the bacteria that causes leprosy. “It’s possible that they can spread it to people,” he said. “People who have occupations or hobbies that put them in potential contact with wildlife should avoid any close contact with armadillos. There’s also a discussion of whether [the spike in leprosy cases] may have to do with climate change. That is not yet confirmed. It’s not entirely clear why there’s been a recent rise. It remains an area of investigation.”
Meanwhile, clinicians should keep a high level of suspicion in patients who present with skin lesions compatible with leprosy. “These are typically discolored or numb patches on the skin,” Dr. Lucar said. “This can range from a single or a few lesions to very extensive involvement of the skin. The diminished sensation or loss of sensation within those skin patches is an important sign. There’s a loss of skin color but sometimes they can be reddish.” He emphasized that leprosy “does not spread easily from person to person; casual contact will not spread leprosy. It’s important for the public to understand that.”
Dr. Lucar reported no disclosures.