Which states in the United States are endemic for leprosy?

States Endemic for Leprosy in the United States

Texas, Louisiana, Hawaii, California, and Florida are the states where leprosy is endemic in the United States, with Florida recently joining this list as an emerging endemic area. 1, 2, 3, 4

Historically Endemic States

The traditional endemic states have remained consistent over several decades:

• Texas, Louisiana, and Hawaii have been recognized as endemic areas since at least the 1980s, accounting for the majority of indigenous (non-imported) U.S. cases 1, 2, 4
• California is considered possibly endemic, with substantial case numbers but less clear evidence of sustained local transmission 5, 4
• These four states accounted for over 80% of reported U.S. cases between 1967-1976 4

Emerging Endemic Area

• Florida has recently been recognized as an endemic state, with increasing incidence rates that now warrant classification as endemic rather than sporadic 3
• The rise in Florida cases includes individuals without known exposure to other leprosy patients or recent travel to endemic countries, suggesting local transmission 3
• Exposure to nine-banded armadillos (Dasypus novemcinctus) or contaminated soil during activities like gardening represents a plausible transmission route in Florida 3

Important Clinical Context

Case Distribution Patterns

• Approximately 90% of U.S. leprosy cases are imported, occurring among immigrants and refugees from endemic countries 5
• The mean annual number of indigenous cases remained stable at 17.7 cases (range 10-29) even during periods of increased imported cases 5
• An epidemic of imported cases occurred from 1978-1988, peaking in 1985 with 307 cases annually, primarily among Southeast Asian refugees, but this did not result in secondary transmission in the United States 5

Geographic Concentration

• Six states (California, Texas, Hawaii, New York, Florida, and Louisiana) accounted for over 80% of cases reported between 1967-1976 4
• New York's high case numbers are primarily due to imported cases among immigrants rather than endemic transmission 4

Transmission Considerations

Physicians in endemic states should maintain a high index of suspicion for leprosy in patients with unexplained skin lesions or peripheral neuropathy, particularly those with:

• Foreign birth from developing countries with high leprosy prevalence 1
• Exposure to armadillos in Texas, Louisiana, Florida, or other southern states 2, 3
• Dermatologic symptoms (hypoesthetic skin lesions, nodular lesions) combined with neurologic findings (palpably enlarged nerves, numbness) 2, 3
• Symptoms that fail to improve despite usual antibiotic therapy 3

Diagnostic Approach in Endemic Areas

• Punch biopsy of skin lesions is the most practical diagnostic method for both multibacillary and paucibacillary types 1
• Skin lesions should be tested for altered sensation (tactile, pain, and thermal) 3
• Examination should include assessment for nerve thickening 3
• Consultation is available through regional Hansen's disease clinics or the National Hansen's Disease Center in Carville, Louisiana 1