Ticks Carrying Lyme Disease Reach Northeast-Level Infection Rates in Western North Carolina Residential Yards
核心洞察
Nearly 40% of adult blacklegged ticks collected from residential yards in Biltmore Forest, North Carolina, tested positive for Borrelia burgdorferi (搜索), the bacterium that causes Lyme disease (搜索).
The infection rate is comparable to parts of the Northeast, mid-Atlantic, and upper Midwest where Lyme disease (搜索) is long established, signaling a southward expansion of the tick vector.
Researchers also detected Borrelia miyamotoi (搜索) and Anaplasma phagocytophilum (搜索), possibly the farthest south these pathogens have been identified in blacklegged tick populations.
Nearly 40 percent of adult blacklegged ticks collected from residential yards in a small town outside Asheville, North Carolina, tested positive for the bacterium that causes Lyme disease (搜索), a rate comparable to parts of the Northeast, mid-Atlantic, and upper Midwest where the illness is long established. The finding, published this week in the CDC's Morbidity and Mortality Weekly Report, marks a striking shift for a region historically considered free of the disease.
"If you were to do a similar study like this in New York or Pennsylvania, you might find 30% or 40% of the ticks are infected, but to see that here in western North Carolina is really striking," said Dr. Ross Boyce, a UNC Health infectious diseases specialist and researcher with the UNC School of Medicine.
Surveillance in a Residential Community
The study was conducted by researchers from the University of South Carolina, the University of North Carolina at Chapel Hill, and North Carolina State University, working with a residents' task force in the town of Biltmore Forest, a residential community in Buncombe County just south of Asheville. Reports from people living there prompted Boyce's team to investigate.
Researchers identified 19 adults who reported having a tickborne illness while living in the community. Of those, 17 self-reported having Lyme disease (搜索). "That's really what sort of perked our ears up and started this whole process, was hearing from community members that they had been having some exposures and getting sick," Boyce said.
Between November 2024 and August 2025, the team collected 373 ticks from 25 residential properties, dragging cloth across vegetation each month at 22 of them and accepting specimens that residents collected themselves. Of those ticks, 287, or about 77 percent, were blacklegged ticks, the primary vector of Lyme disease (搜索) in the eastern United States.
Testing at CDC's vector-borne disease laboratory in Fort Collins found 19 of 48 adult blacklegged ticks, or 39.6 percent, positive for Borrelia burgdorferi (搜索), the bacterium that causes Lyme disease (搜索), along with three of seven nymphs. "We did this in a residential community. That's actually representative of the risk that people more likely face, than if we had gone out into the middle of the national forest," Boyce said. "Realizing that it can be this high risk within a community is really important."
Earlier surveys of public lands in surrounding Buncombe County found infection rates of 13 to 17 percent in nymphs and 25 percent in adults. Because these ticks came from residential yards rather than trails, the authors write that the higher figure suggests greater potential for human disease than previous work indicated.
Additional Pathogens Detected
Lyme disease (搜索) was not the only potential health risk researchers detected. Investigators also found Borrelia miyamotoi (搜索) in two adults and two larval pools, and the human active strain of Anaplasma phagocytophilum (搜索) in four adults. Both can cause serious illness. The MMWR report notes these may represent the farthest south those two pathogens have been identified in blacklegged tick populations.
"As much as we're trying to raise awareness about people around Lyme disease (搜索), now we've suddenly got these other two tick-borne diseases that can cause important disease," Boyce said. "Now they're suddenly down here as well."
A Diagnostic Gap
The research grew out of a resident's long search for an answer. Angela Newnam, now a co-author, spent years pursuing a diagnosis after a bite she got doing yard work in 2015 was initially attributed to a spider. She eventually tested positive for Lyme-related antibodies and worked with town leaders to organize local tick surveillance, which led to the town task force and, in turn, to the research partnership.
"If you find a doctor practicing in western North Carolina who was trained in the mid-90s or earlier, they would've been taught that there was no Lyme disease (搜索) in North Carolina, and a lot of people still have that mentality," Michael Reiskind, an NC State entomologist and study co-author, told Asheville Watchdog.
Boyce framed the stakes in terms of timing. "Lyme disease (搜索) can be a life-changing diagnosis, especially if not diagnosed and treated early," he said in a university statement. "The pace at which we've gone from zero-to-sixty, essentially within a 10-year period, means that we are behind."
"I did my medical school here in Chapel Hill, and the teaching at that point was there's not much, if any, Lyme disease (搜索) in North Carolina," Boyce added. "What we've really been trying to do is sort of raise up the red flag and say hey, this is something you really need to pay attention to and be ready for."
Study Limitations
This is tick surveillance, not a human incidence study, and the authors list five limitations plainly. The community survey drew a 12.5 percent response rate, which raises the risk of selection bias. Most of the 19 reported human tickborne illnesses were self-reported, and only four people provided medical records. The collection began shortly after Hurricane Helene, and no comparable pre-storm data exist. Monthly collection over one to three days at a time, across a small dragging area, limits conclusions about tick density and seasonality.
None of that undercuts the pathogen finding, which came from laboratory testing of individual ticks rather than from recollection. What it means is that the report establishes elevated exposure risk in a specific place, not a countywide case count. Several authors also disclosed relevant support, including funding from the state health department for tick surveillance, consulting income from a company that makes repellent-treated clothing, and membership on a diagnostic scientific board.
Clinical and Public Health Implications
State guidance already reflects the shift. North Carolina public health officials recommend post-exposure preventive treatment with a single dose of doxycycline under specific conditions for people living in or traveling to ten counties: Buncombe, Madison, Yancey, Mitchell, Avery, Watauga, Ashe, Alleghany, Surry, and Stokes. Those counties were selected because they had a high incidence of human Lyme disease (搜索) or sit between two high-incidence counties, according to state guidance for clinicians. Buncombe, where Biltmore Forest sits, is the southernmost.
Clinicians order Lyme testing when they are prompted to consider it, so patients in the region benefit from mentioning outdoor exposure directly rather than waiting to be asked. An expanding rash at a bite site, particularly one that clears in the center, is the classic sign, though it does not always appear. Fever, chills, headache, fatigue, muscle and joint aches after outdoor time are worth reporting. Later stage signs include facial drooping, migrating joint swelling, heart rhythm irregularities, and neurological symptoms such as numbness, neck stiffness, or vision changes. Fever with severe fatigue and no rash can point toward anaplasmosis or a Borrelia miyamotoi (搜索) infection, which requires different consideration than Lyme alone.
Boyce noted that Lyme disease (搜索), unlike some other tickborne illnesses, takes time to transmit. "It does take the tick a while to actually transmit the bacteria to the person," he said, estimating around 24-36 hours for most infected ticks to transmit the bacteria to a human. "If you find a tick pretty quick and get it off, you're probably safe. The problem, especially in the spring, is the ticks are really small. They're sesame seed size, and not as easy to find."
To reduce risk, particularly when traveling in the Winston-Salem or Hickory areas of the state, Boyce recommends wearing a repellent such as DEET, doing frequent tick checks after being outdoors, and keeping grass mowed short. CDC guidance calls for EPA-registered repellent, permethrin-treated clothing, long pants tucked into tall socks, a full body check after time outdoors, and showering soon after coming inside. Yard measures that discourage deer and rodents reduce the local tick burden.
The research team is working with the town on a response plan that includes reducing tick populations and improving access to appropriate care, and is expanding surveillance into more rural counties around Asheville. The authors also recommend a public health alert for primary care, urgent care, and infectious disease clinicians in the region, which would be the next concrete step to watch for.