PR Newswire·Sep 21, 2026, 8:03 AM ET

Nearly 1 in 3 Patients with Suspected Lyme Disease are Co-Positive for Other Tick-Borne Pathogens, Finds Study by Quest Diagnostics

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A study of 193,260 U.S. patients published in JAMA Network Open found that individuals with Lyme disease antibodies are over four times more likely to have antibodies against other tick-borne pathogens.
Nearly one in three patients (29.5%) with antibodies against Borrelia burgdorferi also tested positive for at least one additional tick-borne pathogen.
The most common co-infections involved pathogens transmitted by the blacklegged tick, specifically Babesia microti and Anaplasma phagocytophilum.
Patients in the Northeastern U.S. were roughly twice as likely to have co-detected antibodies against non-Lyme pathogens compared to those in the Midwest, South, or West regions.
Babesia antibodies were most frequently co-detected in the Northeast, reaching 18.5% among patients seropositive for B. burgdorferi.
Over 40% of diagnostic testing occurred during summer months (June through August), with nearly 26% occurring in the fall (September through November).
The study cohort was primarily from the Northeast (70.6%), reflecting known tick habitats, though the dataset covered the entire nation.
Researchers emphasize that comprehensive testing is critical because Babesia requires different antimicrobial treatment than Lyme disease, which is typically treated with doxycycline or amoxicillin.
CDC estimates indicate approximately 476,000 people are diagnosed with Lyme disease annually in the United States.
The study utilized de-identified serological data from Quest Diagnostics and the University of North Carolina at Chapel Hill, covering the period from January 2021 to December 2025.
A limitation of the study is that serological results may reflect past exposure to pathogens rather than confirmed active infections.