Lyme Disease in Ohio: Growing Risk Beyond Endemic Areas
Lyme disease Ohio risk is increasing as black-legged ticks continue to expand across the state. This trend challenges the long-standing belief that Lyme disease is limited to traditionally endemic regions.
Deer tick distribution in Ohio (Glenn Needham)
Over a five-year period, researchers from Ohio State University and the Ohio Department of Health documented a significant increase in black-legged ticks (Ixodes scapularis)—the primary vector of Lyme disease. [1]
This increase has been accompanied by a doubling of reported Lyme disease cases in the state.
Evidence of an Established Cycle
The study, published in Frontiers in Cellular and Infection Microbiology, found deer ticks in 57 of Ohio’s 88 counties as of 2012.
Researchers confirmed the full enzootic life cycle of Borrelia burgdorferi, the bacterium responsible for Lyme disease.
This means Lyme disease is no longer emerging in Ohio—it is established.
The presence of larvae, nymphs, and adult ticks indicates sustained transmission within the environment.
Why Ticks Are Spreading
The expansion of deer ticks in Ohio has been attributed to several factors:
- Migratory birds transporting infected ticks
- Deer movement across regions
- Human environmental changes
These factors allow Lyme disease to spread into areas previously considered low risk.
The Surveillance Problem
Despite growing evidence, the CDC has historically classified Ohio as a non-endemic state.
This classification may underestimate actual risk.
Ohio’s own tick surveillance program—operating since 1983—provided valuable data but lost funding and was discontinued in 2012.
Without consistent surveillance, emerging risk may go unrecognized.
Why This Matters Clinically
Physicians often rely on CDC surveillance maps when assessing Lyme disease risk.
If a region is considered low risk, Lyme disease may not be included in the differential diagnosis.
This can lead to:
- Delayed diagnosis
- Missed treatment opportunities
- Progression to chronic illness
The consequences of under-recognition can be significant.
The “Non-Endemic” Myth
At our practice, we have treated patients from across the United States—including those infected in states traditionally labeled as non-endemic.
Lyme disease does not respect geographic boundaries.
As tick populations expand, the concept of “non-endemic” regions becomes less reliable.
Clinical Perspective
Clinicians should consider Lyme disease in patients with compatible symptoms—even in areas not officially recognized as endemic.
Geographic assumptions should not replace clinical judgment.
Early recognition and treatment remain critical to preventing long-term complications.
For more information on ticks and the diseases they transmit, visit:
About ticks and tick-borne diseases
References
- Wang P, Glowacki MN, Hoet AE et al. Emergence of Ixodes scapularis and Borrelia burgdorferi in Ohio. Front Cell Infect Microbiol, 2014.
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
