Study finds ticks carrying Lyme disease moving into western NC

North Carolina is experiencing a surge in Lyme disease cases, and a new surveillance study from UNC Greensboro (UNCG) reveals that the primary vector of the bacteria that cause Lyme disease, the blacklegged tick (Ixodes scapularis), has been spreading into areas previously considered low risk.

“Currently, 16 states, mostly in the Northeast, mid-Atlantic, and upper Midwest, account for 95% of the reported LD cases,” says Dr. Gideon Wasserberg, a biology professor at UNCG and one of the research project leaders. “However, low-incidence states to the south and west, including North Carolina, have experienced an increase in the number of reported Lyme disease cases since the early 2010s.”

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With funding from Centers for Disease Control, administered by the North Carolina Department of Health and Human Services, researchers from UNCG, North Carolina State University, and Appalachian State University conducted a five-year, statewide survey of blacklegged ticks and the pathogens they often carry.

“Our data shows a range expansion of these ticks into more counties in the Blue Ridge Mountains and the western Piedmont region and a dramatic increase in their densities in this area as a whole,” said Wasserberg. “These findings are consistent with increasing reports of human Lyme disease cases in these areas.” 

Established ticks

Eastern Piedmont and the Coastal Plain, where blacklegged ticks and human Lyme disease cases have been historically noted, saw little change in tick density in comparison. 

In the new study, ticks from the Blue Ridge Mountains were also more likely to carry Borrelia burgdorferi, the bacteria responsible for most cases of Lyme disease, compared to ticks from the Piedmont and Coastal Plain. 

“Our analyses indicate that these ticks and the bacteria they carry moved into the Blue Ridge Mountains of North Carolina from southwestern Virginia over the last 10 years, travelling along the Appalachian Mountains,” says Wasserberg.

Health implications

The researchers say the findings have important implications for public health.

“Enhanced surveillance, increased public awareness, and updated guidance for healthcare providers are crucial to mitigate risk.” said Dr. Reuben Garshong, the lead author of the newly published article in PLOS One. 

Now a research scientist at the New Jersey Department of Health, Garshong participated in much of the study as a doctoral student in Wasserberg’s lab at UNCG.