Lyme Disease Co-Infections: Symptoms, Testing, and Treatment
Ticks may transmit multiple infections in a single bite
Co-infections can worsen symptoms and complicate treatment
Babesia, Bartonella, Anaplasmosis, and Ehrlichia are increasingly recognized
Lyme disease co-infections occur when a tick transmits multiple infectious organisms during a single bite.
These co-infections may worsen symptoms, complicate diagnosis, and require different treatment approaches than Lyme disease alone.
Common Lyme disease co-infections include Babesia, Bartonella, Anaplasmosis, Ehrlichia, STARI, and Borrelia miyamotoi.
The Centers for Disease Control and Prevention (CDC) now reports that a single tick may transmit multiple pathogens, including bacteria, parasites, and viruses.
For many patients, co-infections help explain why symptoms become more severe, persistent, or resistant to standard Lyme disease treatment.
Watch: Understanding Lyme disease co-infections and why they may complicate recovery.
Why Lyme Disease Co-Infections Matter
Ticks increasingly harbor multiple infectious organisms.
Studies from Lyme-endemic regions have found that many black-legged ticks carry more than one pathogen simultaneously.
Researchers have reported co-infection rates approaching 28% in some endemic areas.
Patients with Lyme disease and co-infections often experience:
- more severe symptoms
- greater neurologic involvement
- longer recovery times
- more complicated treatment courses
- persistent fatigue and cognitive dysfunction
Some co-infections may also increase the duration and severity of illness compared to Lyme disease alone.
Common Lyme Disease Co-Infections
The most commonly recognized Lyme disease co-infections include:
- Babesia
- Bartonella
- Anaplasmosis
- Ehrlichia
- STARI
- Borrelia miyamotoi
Each infection may produce overlapping symptoms while also requiring different diagnostic and treatment approaches.
Babesia
Babesia is a parasite that infects red blood cells and is commonly transmitted through tick bites.
Most human infections involve Babesia microti or Babesia duncani.
Symptoms may include:
- night sweats
- air hunger
- fatigue
- fevers and chills
- dizziness
- exercise intolerance
Babesia and Lyme disease commonly occur together and may worsen symptom severity and prolong recovery.
Importantly, doxycycline alone does not eradicate Babesia.
Babesia treatment may require antiparasitic medications such as atovaquone combined with azithromycin.
Bartonella
Bartonella species have been identified in black-legged ticks and may contribute to neurologic and psychiatric symptoms in some patients.
Symptoms may include:
- burning foot pain
- streak-like rashes
- anxiety or panic symptoms
- cognitive dysfunction
- fatigue
- swollen glands
Several studies have described neuropsychiatric presentations associated with Bartonella infection.
Anaplasmosis
Anaplasmosis is caused by Anaplasma phagocytophilum and may resemble Lyme disease or Ehrlichiosis.
Symptoms may include:
- fever
- headaches
- muscle aches
- malaise
- chills
Although many cases are mild, some patients require hospitalization.
Anaplasmosis can often be treated with doxycycline.
Ehrlichia
Ehrlichia infects white blood cells and is transmitted primarily by the Lone Star tick.
Symptoms may include:
- fatigue
- fever
- headaches
- muscle aches
If untreated, Ehrlichiosis may become severe and require hospitalization.
Borrelia miyamotoi
Borrelia miyamotoi causes a relapsing fever-type illness that may resemble Lyme disease without rash.
Symptoms may include:
- fever
- headache
- fatigue
- muscle aches
- chills
Diagnostic testing remains limited, and some studies suggest the infection may be transmitted rapidly after tick attachment.
Why Co-Infections Are Often Missed
Testing for Lyme disease co-infections remains inconsistent in clinical practice.
One study found that only a minority of patients undergoing Lyme disease testing were also tested for non-Lyme tick-borne diseases.
Symptoms frequently overlap, making diagnosis more complicated.
In clinical practice, co-infections should be considered when symptoms are unusually severe, persistent, or resistant to standard therapy.
Persistent symptoms after Lyme disease treatment may sometimes reflect untreated co-infections rather than Lyme disease alone.
Testing and Treatment Challenges
Testing limitations remain a major challenge in diagnosing Lyme disease co-infections.
Some infections may be difficult to detect early in illness or may require specialized testing.
Treatment also varies significantly between infections.
For example:
- doxycycline may treat Anaplasmosis and Ehrlichia
- Babesia requires antiparasitic therapy
- some Bartonella infections may require combination antibiotic approaches
Accurate diagnosis is important because treatment effective for one co-infection may not adequately treat another.
Frequently Asked Questions
What are Lyme disease co-infections?
Lyme disease co-infections occur when a tick transmits multiple infectious organisms during a single bite.
What symptoms suggest Lyme disease co-infections?
Symptoms may include night sweats, air hunger, severe fatigue, dizziness, psychiatric symptoms, persistent fevers, and prolonged recovery.
Does doxycycline treat all Lyme disease co-infections?
No. Doxycycline may treat some bacterial co-infections, but it does not eradicate Babesia.
Which Lyme disease co-infections are most common?
Common co-infections include Babesia, Bartonella, Anaplasmosis, Ehrlichia, STARI, and Borrelia miyamotoi.
Can Babesia occur with Lyme disease?
Yes. Babesia frequently occurs alongside Lyme disease and may worsen symptom severity.
Why are Lyme disease co-infections missed?
Co-infections are often missed because symptoms overlap and testing may not routinely include non-Lyme tick-borne infections.
Clinical Takeaway
Lyme disease co-infections are increasingly recognized and may significantly worsen symptom severity, complicate diagnosis, and prolong recovery.
Different co-infections often require different treatment approaches, making accurate recognition clinically important.
Persistent or unusually severe symptoms after Lyme disease treatment should prompt consideration of Babesia or other untreated co-infections.
Related Articles
These related articles explore Babesia, Borrelia miyamotoi, autonomic dysfunction, persistent symptoms, and challenges associated with tick-borne co-infections.
Tafenoquine for Relapsing Babesia
Challenges Diagnosing Borrelia miyamotoi
Autonomic Dysfunction in Lyme Disease
Post-Treatment Lyme Disease Syndrome
Persistent Lyme Disease
References
- CDC Vital Signs: Trends in Tickborne Disease. MMWR. 2018.
- Mohan KVK, Leiby DA. Emerging tick-borne diseases and blood safety. Transfusion. 2020.
- Saetre K, et al. Congenital Babesiosis After Maternal Infection With Borrelia burgdorferi and Babesia microti. JPIDS. 2018.
- Rocco JM, et al. Severe anaplasmosis and hemophagocytic lymphohistiocytosis. Ticks Tick Borne Dis. 2020.
- Rivera JE, et al. Anaplasmosis Presenting With Respiratory Symptoms and Pneumonitis. Open Forum Infect Dis. 2020.
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
Thank you! My daughter just tested positive for Babesia Duncani and Bartonella Bacilliformis. I am thankful to find your blog! There is one Lyme specialist in our state and I understand he sometimes has a 6-month waiting list. So the info you share is very helpful to us!
What are the tests for lymes disease co- infections? How does one find a doctor that specializes in lymes disease? I’m in Arizona, and was diagnosed 20 years ago.