Lyme Co-Infections: Why Symptoms Persist
Ticks can carry multiple infections.
That can change recovery.
Lyme co-infections are common and may explain why some patients continue to experience symptoms despite treatment.
Ticks can transmit more than one pathogen at the same time, including Babesia, Bartonella, Anaplasma, and Rickettsia.
Clinical reality: treating Lyme disease alone may not be enough.
How Common Are Lyme Co-Infections?
Studies suggest co-infections are not rare:
- Up to 40% of Lyme patients may have Babesia
- Approximately 13% may have Anaplasma
- Ticks in endemic regions are often co-infected
Key point: a single tick bite can transmit multiple infections.
A single tick bite may expose you to more than one infection.
Why Lyme Co-Infections Matter
Co-infections can change the clinical picture.
Patients with co-infections may experience:
- More severe symptoms
- Longer duration of illness
- Reduced response to standard Lyme treatment
Clinical insight: persistent symptoms are not always treatment failure—they may reflect untreated co-infections.
Symptoms of Lyme Co-Infections
Different co-infections are associated with different symptom patterns:
- Babesia: night sweats, air hunger, fatigue
- Bartonella: anxiety, irritability, neurologic symptoms
- Anaplasma/Ehrlichia: fever, chills, muscle aches
Clinical pattern: symptoms that do not fully match Lyme disease—or do not improve with treatment—may suggest co-infection.
Why Co-Infections Are Often Missed
Co-infections are not always routinely evaluated.
Testing may be limited, and symptoms often overlap with Lyme disease.
Clinical gap: real-world exposure risk may exceed current testing practices.
Why Treatment May Be Incomplete
Different infections require different therapies.
- Doxycycline treats Lyme disease but does not treat Babesia
- Babesia requires antiparasitic treatment
Clinical takeaway: incomplete treatment may occur if co-infections are not identified.
This may result in:
- Partial improvement
- Relapse after treatment
- Persistent symptoms
Lyme co-infections can increase symptom severity, prolong illness, and affect treatment response. Identifying them is important for recovery.
Final Thought
Lyme disease is often more than one infection.
Recognizing co-infections can help explain why symptoms persist and why recovery may vary.
Key question: Could persistent symptoms be due to an undiagnosed co-infection?
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
Dear Dr Cameron
Despite tearing ahowing my daughter had Lyme and babesia the doctors refused anything other than a round of doxycycline. That cleared up some of the symptoms she had but not others. The doctors here are amazingly out to lunch on Lyme. Can you recommend a doctor as she has developed arthritis in her joints, fingers etc and has been tested for everything else. She need both drugs you recommend for both the babesia and left over Lyme syamtpoms.
You might find a doctor familiar with Babesia and other tick borne illnesses by contacting the Lyme Disease Association, Global Lyme Alliance and ILADS. You could also call my office in New York at 914 666 4665.
Thank you for the written and well referenced article. Nova Scotia is finally doing routine tests for Babesia and Anaplasma. The commonest species of Babesia in Canada is B. odecoilei. Deer are the reservoir and it can kill.