The United States reports between 124 and 216 new cases of leprosy (Hansen’s disease) each year, based on data from 2013 through 2022. In 2020, 159 new cases were reported nationwide. While those numbers are small compared to the roughly 200,000 cases diagnosed globally each year, the trend in the U.S. is moving in a notable direction: cases have been gradually increasing, particularly in the Southeast.
Where Cases Are Concentrated
Leprosy in the U.S. is not evenly distributed. Florida, Texas, Louisiana, Hawaii, and New York have historically reported the most cases. Over the past decade, southeastern states have seen their case counts more than double, with Florida consistently ranking among the top reporting states.
What makes this shift significant is who is being diagnosed. For years, the majority of U.S. leprosy cases were linked to people who had lived in or traveled to countries where the disease is more common. But since 2002, the rate of new diagnoses among people born outside the United States has actually been declining. That means a growing share of cases are appearing in people with no clear international exposure, suggesting low-level local transmission may be occurring, particularly in parts of Florida and the Gulf Coast.
How Leprosy Spreads
Leprosy is caused by a slow-growing bacterium that primarily affects the skin and peripheral nerves. It spreads through prolonged, close contact with an untreated person, most likely through respiratory droplets from coughing or sneezing. Casual contact, like shaking hands or sitting next to someone, does not transmit it.
The bacterium grows extremely slowly. The incubation period averages about five years but can stretch to 20 years, which makes it difficult to pinpoint where or when someone was exposed. In the southern U.S., nine-banded armadillos are a known animal reservoir. Some locally acquired cases have been linked to armadillo contact, though many patients report no direct exposure to the animals.
About 95% of people are naturally immune to the bacterium and will never develop the disease even if exposed. This is one reason it remains rare despite being an ancient infection.
Symptoms and Diagnosis
Because of the long incubation period, symptoms develop gradually. The earliest sign is usually a patch of skin that looks lighter or redder than surrounding areas and feels numb to touch or temperature. Nerve damage can cause tingling, weakness, or loss of sensation in the hands and feet. Left untreated, the nerve damage can become permanent, leading to muscle weakness, claw-like deformities in the hands, and chronic wounds from injuries a person can’t feel.
Diagnosis typically involves a skin biopsy. Because leprosy is so uncommon in the U.S., many doctors have never seen a case, which can lead to delays. The average time between symptom onset and diagnosis in the U.S. is often a year or more.
Treatment and Recovery
Leprosy is fully curable with antibiotics. The standard treatment uses a combination of three drugs taken for 6 to 12 months, depending on the severity. Milder cases with fewer skin lesions and lower bacterial counts require six months of treatment. More advanced cases with widespread skin involvement need a full year.
Once treatment begins, a person becomes noncontagious within days. Nerve damage that occurred before treatment may not fully reverse, which is why early diagnosis matters. Most people treated promptly recover completely without lasting complications.
The Federal Treatment Network
The U.S. runs a dedicated program for leprosy care called the National Hansen’s Disease Program, managed by the Health Resources and Services Administration. It operates a network of federally supported outpatient clinics across the country where anyone living in the U.S. or its territories can receive diagnosis and treatment for leprosy at no cost.
These clinics are located in major cities including Atlanta, Boston, Chicago, Los Angeles, Miami, New York, Phoenix, San Diego, and Seattle, along with several sites in Texas (which has the most clinics of any state), a clinic in Springdale, Arkansas, and one in San Juan, Puerto Rico. In total, there are roughly 16 clinic locations. For people who don’t live near one of these sites, the program can coordinate care with local providers.
Why Cases Are Rising in the Southeast
The increase in southeastern states has drawn attention from public health researchers. A 2023 CDC case report highlighted central Florida as an area of particular concern, noting that the region’s cases increasingly involve people with no history of foreign travel, no known contact with other leprosy patients, and no reported armadillo exposure. This pattern suggests the disease may be becoming endemic at low levels in parts of the region, meaning it circulates locally rather than being imported from abroad.
The absolute numbers remain small, and the risk to any individual is extremely low. But the upward trend has prompted calls for greater awareness among clinicians in affected areas so that cases are caught earlier and nerve damage is prevented.