Lyme Disease Ticks Move South: Blacklegged Ticks in Western North Carolina

Lyme disease, the most commonly reported vector-borne disease in the United States, has long been concentrated in the Northeast and upper Midwest. But cases have been rising in the Southeast, particularly along the Appalachian Mountains. In southern Appalachia, Lyme disease is emerging but not yet considered endemic.

A community asks for help

Biltmore Forest is a heavily wooded town of about 1,600 acres in North Carolina's Blue Ridge Mountains, between the Biltmore Estate and Asheville. When residents grew concerned about more tick-borne illness, a community task force teamed up with researchers from the University of North Carolina at Chapel Hill, North Carolina State University and the University of South Carolina.

In early 2024, the task force mailed surveys to about 600 households; 75 responded. Counting referrals from neighbors, 19 people in 17 households reported at least one tick-borne diagnosis while living in the town:

• Lyme disease: 17
• babesiosis: 2
• ehrlichiosis: 1

(Two reported coinfections, and one couldn't recall the disease.) Only four provided medical records: one showed laboratory evidence of Lyme infection, two showed the erythema migrans rash after a tick exposure, and one showed no evidence of infection.

Collecting ticks

From November 2024 to August 2025, researchers dragged cloth across 22 residential yards each month (May 2025 was rained out), and residents mailed in ticks they found on themselves, their pets or their property. Ticks went to the University of South Carolina for identification and DNA extraction, and Ixodes ticks were tested for pathogens at CDC's Division of Vector-Borne Diseases in Fort Collins, Colorado.

What the ticks carried

No ticks tested positive for Babesia microti, Ehrlichia muris eauclairensis or Borrelia mayonii.

Self-reported tick-borne disease and pathogens in collected ticks, Biltmore Forest. Credit: Centers for Disease Control and Prevention.

Why it matters

• Infection rates like the Northeast's. The share of adult blacklegged ticks carrying the Lyme bacterium matches the mid-Atlantic, upper Midwest and Northeast, where Lyme is endemic. Earlier studies on public land in Buncombe County found 13%–17% of nymphs and 25% of adults infected; because these ticks came from yards, the higher rate here suggests greater potential for human disease.
• The leading edge. Surveys in neighboring South Carolina counties found little infection, suggesting Biltmore Forest marks the leading edge of northern blacklegged ticks spreading south. Finding host-seeking nymphs also points to northern-lineage ticks in the state.
• New pathogens, farther south. These may be the southernmost findings yet of the human-infecting strain of A. phagocytophilum and of B. miyamotoi in blacklegged ticks — both can cause severe illness.

Limitations

• Collection began shortly after Hurricane Helene devastated western North Carolina; with no earlier data, its effect on ticks is unknown.
• Ticks were collected on only 1–3 days a month, in varying weather, over a small area.
• The survey's 12.5% response rate risks bias, and most illnesses were self-reported.

What to do

• Clinicians in the region — especially in primary care, urgent care and infectious disease — should consider Lyme and other tick-borne diseases in people who live in or visit the area; many have little experience diagnosing them.
• Public health should expand blacklegged tick surveillance and pathogen testing across the Southeast.
• Everyone can prevent bites: wear long pants and tall socks, use EPA-registered insect repellent, and check for ticks after time outdoors. See CDC's tick bite prevention guidance.

Sources

Based on Sweeney S, Bullock A, Reiskind M, et al., "Southward Expansion of Ixodes scapularis (Blacklegged) Tick Pathogens — Western North Carolina, November 2024–August 2025," Morbidity and Mortality Weekly Report 75(31), Centers for Disease Control and Prevention; a work of the United States government in the public domain. Original report.