Lyme Disease Co-infections
Other Infections That Often Accompany Lyme Disease
Up to 45% of blacklegged ticks carry more than one pathogen and can transmit multiple infections.
Lyme Disease Co-infections Worsen Symptoms
Lyme disease is commonly thought of as one infection caused by the bacterium Borrelia burgdorferi, transmitted through the bite of a blacklegged tick. However, co-infections — where multiple pathogens are transmitted in a single tick bite — are more common than many realize. These may include bacteria, viruses, fungi, and protozoa.
These Lyme disease co-infections often lead to more severe illness, a wider range of symptoms and a more complicated recovery.
Medical professionals are encouraged to consider the possibility of co-infections — especially Babesia and Anaplasma — when patients with Lyme disease experience unusually intense symptoms or fail to improve with treatment. Other coinfections may also be involved and should not be overlooked.
How Common Are Co-infections?
In the northeastern U.S., studies have found that up to 45% of blacklegged ticks carry more than one pathogen ─ meaning that a single tick bite can result in co-infections. And, up to a third of individuals diagnosed with Lyme disease may also have at least one co-infection.
A survey conducted in endemic regions reported that nearly 1 in 5 people with Lyme disease also tested positive for the co-infection babesiosis.
While anaplasmosis and ehrlichiosis are less common, they still impact up to 10% of Lyme patients. And recent data indicates that the number of cases of Borrelia miyamotoi, another coinfection, is on the rise.
Top Co-infections in Lyme Disease Patients
According to a survey by Lymedisease.org, out of 3,000 patients with chronic Lyme disease, over 50% had co-infections, with 30% reporting 2 or more. The most common Lyme disease co-infections include: Babesiosis (32%), Bartonella (28%), Ehrlichia (15%), Mycoplasma (15%), Rocky Mountain spotted fever (6%), and Anaplasma (5%).
However, in a Canadian study by Sperling and Associates, the most common co-infections found in patients with Lyme disease were Bartonella (36%) and Babesia (19%), followed by Anaplasma (13%). The specific co-infections people develop can vary depending on geography.
Note: While both ticks and humans are known to carry Bartonella, scientists are still studying the exact way this infection is transmitted.
Why Lyme Disease Co-infections Matter
01
More Severe Illness:
Co-infections often lead to more intense symptoms and longer recovery times.
02
Complicated Diagnosis:
Lab tests may not detect all infections at once, and symptoms often overlap.
03
Treatment Differences:
While Lyme disease is treated with antibiotics like doxycycline, Babesia requires anti-parasitic medications. Missing a co-infection can result in incomplete treatment.
Note: The information presented on this page has been reviewed and approved by a member of our Medical Leadership Board.