Is Lyme Disease Moving Farther South?
Infected blacklegged ticks were found around homes in western North Carolina
Approximately 40% of tested adult blacklegged ticks carried the Lyme bacterium
Emerging risk may outpace surveillance maps and clinical awareness
Lyme disease has traditionally been associated with the Northeast, mid-Atlantic, and upper Midwest. Patients in southern states may therefore be told that Lyme disease is unlikely because they do not live in a recognized endemic area.
A 2026 report from the Centers for Disease Control and Prevention provides important evidence that this geographic assumption needs to be reconsidered. Researchers found blacklegged ticks carrying Borrelia burgdorferi, the bacterium that causes Lyme disease, on residential properties in western North Carolina.
Nearly 40% of the adult blacklegged ticks tested were infected. The researchers also detected pathogens associated with anaplasmosis and hard tick relapsing fever.
The study does not mean that Lyme disease risk is now uniform throughout North Carolina or the entire South. It does show that infected blacklegged tick populations can become established in locations that have not historically been considered endemic.
What did researchers find in western North Carolina?
Researchers conducted community-based tick surveillance in Biltmore Forest, a heavily wooded residential community near Asheville, North Carolina. Local residents had raised concerns about increasing numbers of tick encounters and tick-borne illnesses.
Ticks were collected monthly from residential properties between November 2024 and August 2025. Investigators used cloth dragging and flagging to collect ticks from the environment. Residents could also submit ticks found on themselves, their pets, or their properties.
A total of 373 ticks were collected. Of these, 287—approximately 77%—were blacklegged ticks, or Ixodes scapularis. This is the tick species principally responsible for transmitting Lyme disease in the eastern United States.
Among the adult blacklegged ticks suitable for testing, 19 of 48, or 39.6%, carried Borrelia burgdorferi. Three of seven tested blacklegged tick nymphs were also positive.
Positive ticks were found across the community rather than being limited to one property. The infection prevalence among the tested adult ticks was similar to levels found in areas of the Northeast, mid-Atlantic, and upper Midwest where Lyme disease is already considered endemic.
Does this mean 40% of North Carolina ticks carry Lyme disease?
No. The approximately 40% infection rate applied to 48 adult blacklegged ticks tested in one small, heavily wooded community. It should not be generalized to all ticks in western North Carolina, the entire state, or the broader Southeast.
The number of tested nymphs was especially small. Although three of seven nymphs carried Borrelia burgdorferi, seven ticks are not enough to establish a reliable regional infection rate.
The study also could not determine tick density throughout the community. Collections occurred during only a few days each month and could have been affected by weather, environmental conditions, and ecological disruption following Hurricane Helene.
These limitations affect how broadly the percentages can be applied, but they do not eliminate the central finding: blacklegged ticks carrying the Lyme disease bacterium were present on multiple residential properties in western North Carolina.
Why does finding infected ticks near homes matter?
Tick exposure is often associated with hiking, camping, hunting, or working in forests. Those are important risks, but they are not the only ways people encounter ticks.
The ticks in this study were collected primarily from residential properties. This means that exposure could occur while gardening, walking a dog, clearing leaves, playing in a yard, or moving between wooded and landscaped areas.
A patient may not remember entering a forest or participating in an obvious high-risk activity. The relevant exposure may have been an ordinary activity close to home.
This finding reinforces why clinicians should ask where a patient lives, where the patient has traveled, and what the patient was doing outdoors. The absence of a wilderness exposure does not exclude the possibility of a tick bite.
Why has Lyme disease historically been reported less often in the South?
Blacklegged ticks have long been present in parts of the southeastern United States, but Lyme disease has been reported less often there than in the Northeast and upper Midwest.
Several factors may contribute. Tick behavior, host animals, vegetation, climate, pathogen prevalence, human outdoor activity, and the likelihood that a person encounters an infected nymph can differ by region.
Southern blacklegged ticks may also behave differently from northern populations. In some southern locations, immature ticks are more likely to remain below the leaf litter and feed on reptiles rather than actively seeking people above the vegetation. This can reduce human contact even when the tick species is present.
The new North Carolina findings suggest that northern blacklegged tick populations may be expanding southward along the Appalachian region. The collection of host-seeking nymphs provides additional evidence that the ecology of Lyme disease risk may be changing.
Patients can learn more about established and emerging regional exposure in Can You Get Lyme Disease in the Southern United States?
Were pathogens other than the Lyme bacterium detected?
Yes. Researchers detected Borrelia miyamotoi in adult blacklegged ticks and larval tick pools. This bacterium can cause hard tick relapsing fever, an illness that may include fever, chills, headache, fatigue, and muscle or joint pain.
The human-active strain of Anaplasma phagocytophilum, which causes anaplasmosis, was also identified in adult blacklegged ticks. Anaplasmosis can cause fever, headache, muscle aches, fatigue, and laboratory abnormalities such as low white blood cell or platelet counts and elevated liver enzymes.
These findings are clinically important because a patient exposed to blacklegged ticks may be at risk for more than one infection. Symptoms, laboratory findings, illness severity, and treatment response may not always be explained by Lyme disease alone.
The study did not detect every pathogen that blacklegged ticks can potentially carry. Absence from this relatively small sample does not establish that another infection is absent throughout the region.
Can Lyme disease occur outside a recognized endemic area?
Yes. An endemic classification describes an established population-level pattern. It does not determine whether an individual patient encountered an infected tick.
Tick populations and pathogens do not stop at state or county lines. Their geographic ranges can change gradually, and surveillance systems may require time to identify and formally recognize an emerging area.
Human case maps have additional limitations. Cases are generally mapped according to a patient’s residence, which may not be where the infection was acquired. A patient could be bitten while visiting another county or state and later become ill after returning home.
The opposite can also occur. A person may acquire Lyme disease locally in an emerging-risk area, but clinicians may assume that exposure was impossible because the region is not yet widely recognized as endemic.
Geography should therefore inform clinical probability without becoming an absolute rule. A complete assessment considers the location and timing of possible exposure, outdoor activities, symptoms, physical findings, testing, and alternative diagnoses.
Could outdated geographic assumptions delay diagnosis?
They can. Lyme disease symptoms may overlap with viral illnesses, autoimmune disorders, neurologic conditions, medication effects, and other tick-borne infections. If Lyme disease is removed from consideration solely because of geography, appropriate examination or testing may be delayed.
This does not mean that every unexplained illness in the South should be diagnosed as Lyme disease. The symptoms remain nonspecific, and competing explanations must still be evaluated.
However, “Lyme disease does not occur here” becomes less defensible when surveillance identifies established blacklegged tick populations carrying Borrelia burgdorferi. A more accurate approach is to acknowledge that regional risk varies and may be evolving.
What exposure information should patients tell their doctors?
Patients should describe more than a known tick bite. Useful details may include:
- Where they live and where they have recently traveled
- Visits to wooded, grassy, brushy, or leaf-covered areas
- Gardening, yard work, dog walking, hunting, camping, or hiking
- Ticks found on family members, pets, clothing, or around the home
- The approximate date and location of any known bite
- Any expanding or unexplained rash, even if it did not resemble a perfect bull’s-eye
- The timing of fever, headache, facial weakness, joint swelling, palpitations, numbness, or other symptoms after possible exposure
Many patients with Lyme disease do not remember a tick bite. Nymphal blacklegged ticks are small and can attach in areas that are difficult to see. The absence of a recalled bite should not be treated as proof that exposure did not occur.
What do these findings mean for people living in or visiting southern Appalachia?
People should not panic or assume that every tick is infected. The study instead supports practical awareness of an emerging risk.
Residents and visitors can reduce exposure by using an Environmental Protection Agency–registered repellent, treating appropriate clothing and gear with permethrin, walking near the center of trails, checking the body after outdoor activity, showering after returning indoors, and checking pets and equipment.
Prevention should extend to activities around the home. Managing leaf litter, brush, and vegetation near frequently used areas may reduce opportunities for contact with ticks.
A person who develops an expanding rash, fever, facial weakness, severe headache, new joint swelling, palpitations, shortness of breath, fainting, or neurologic symptoms after possible tick exposure should seek medical evaluation. Urgent or severe symptoms require prompt care rather than waiting for a routine appointment.
Frequently Asked Questions
Is Lyme disease now common throughout the South?
No. Lyme disease risk is not uniform throughout the South. The North Carolina study documented an emerging area of risk in one western community, but its findings cannot be applied to every southern state or county.
Did 40% of all ticks in the North Carolina study carry Lyme disease?
No. Approximately 40% of the tested adult blacklegged ticks carried Borrelia burgdorferi. The percentage does not apply to all tick species, all collected ticks, or all ticks in North Carolina.
Can someone get Lyme disease without hiking or camping?
Yes. Infected ticks may be encountered during gardening, yard work, walking a dog, or other ordinary activities around wooded residential properties.
Should Lyme disease be excluded if a patient lives outside a recognized endemic area?
No. Geography affects the likelihood of Lyme disease, but it should not be used as an absolute exclusion. Travel, local outdoor exposure, symptoms, physical findings, test timing, and alternative diagnoses should all be considered.
What other pathogens were found in the North Carolina ticks?
Researchers also detected Borrelia miyamotoi and the human-active strain of Anaplasma phagocytophilum. These pathogens can cause hard tick relapsing fever and anaplasmosis, respectively.
Clinical Takeaway
The western North Carolina study does not establish that Lyme disease risk is equally high across the South. It does provide evidence that infected blacklegged tick populations are becoming established farther south and can be found around residential properties.
Clinical suspicion should reflect current exposure evidence rather than depend entirely on historical endemic boundaries. Patients still require an individualized assessment that considers symptoms, competing diagnoses, testing limitations, and the complete geographic and activity history.
“Not traditionally endemic” should not be interpreted as “Lyme disease is impossible.”
Related Articles
Why Travel History Matters When Evaluating Lyme Disease
What Are the Bad Signs After a Tick Bite?
References
- Sweeney, S., Bullock, A., Reiskind, M., Newnam, A., Kanipe, J., Nolan, M. S., Boyce, R. M., & North Carolina Biltmore Forest Study Team. Southward expansion of Ixodes scapularis (blacklegged) tick pathogens—Western North Carolina, November 2024–August 2025. MMWR Morbidity and Mortality Weekly Report. 2026;75(31):398–402.
- Ginsberg, H. S., Hickling, G. J., Burke, R. L., Ogden, N. H., Beati, L., LeBrun, R. A., Arsnoe, I. M., Gerhold, R., Han, S., Jackson, K., Maestas, L., Moody, B., Pang, G., Ross, B., Rulison, E. L., Tsao, J. I., & Mather, T. N. Why Lyme disease is common in the northern US, but rare in the south: The roles of host choice, host-seeking behavior, and tick density. PLOS Biology. 2021;19(1):e3001066.
- Centers for Disease Control and Prevention. Lyme disease case maps. CDC. 2025.
This article is for informational purposes only and does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional regarding individual symptoms or possible tick exposure.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
