Babesia Risk Expanding—or Being Missed?
Tick exposure outside known areas?
Symptoms worse than expected for Lyme?
Babesia infection may be overlooked.
What if the infection is present—but not recognized? Babesia risk is expanding across the United States, including regions not traditionally considered endemic.
A key pattern is geographic shift. Tick-borne infections are no longer confined to historically recognized areas.
Learn more about Babesia infections.
Babesia Risk Identified in New Areas
A large citizen-based study analyzed more than 16,000 ticks collected directly from people and their environments.
A key pattern is real-world exposure. This approach captures risk that traditional surveillance may miss.
Babesia microti was identified in multiple tick species, including:
- Lone star ticks (2.5%)
- Deer ticks (1.8%)
These findings suggest potential expansion beyond traditional transmission patterns.
Babesia and Lyme Co-Infection
A key pattern is overlap. Babesia often occurs alongside Lyme disease.
In some regions, up to 40% of patients with Lyme disease may also have Babesia infection.
This combination can lead to more severe or prolonged illness.
See Lyme disease co-infections.
States Where Babesia Risk May Be Emerging
Babesia-infected ticks were identified in areas not previously considered endemic, including:
- Alabama
- Arkansas
- Indiana
- Mississippi
A key pattern is expansion. Risk may extend beyond historically recognized regions.
Why Babesia May Be Missed
A key pattern is diagnostic gap. Babesia is not always considered in patients with tick exposure.
- Symptoms overlap with Lyme disease
- Focus remains on a single infection
- Geographic assumptions limit suspicion
- Testing may not always be performed
This contributes to under-recognition of co-infections.
Clinical Perspective
Babesia infection should be considered in patients with tick exposure—even outside known endemic areas.
Recognition depends on considering co-infections when symptoms are more severe or prolonged than expected.
Clinical Takeaway
Babesia risk is expanding geographically and may be underrecognized.
If symptoms are more severe than expected for Lyme disease alone, evaluation for Babesia may be warranted.
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
