Babesia vs Anaplasmosis: Confusion in an Elderly Woman
Babesiosis and anaplasmosis can occur together
Coinfection may cause confusion, anemia, and low blood counts
Early recognition and combination treatment may improve outcomes
Welcome to an Inside Lyme case study. One of the best ways to understand anaplasmosis and babesiosis is by reviewing real patient cases. This case highlights how coinfection with these two tick-borne diseases led to confusion, anemia, and abnormal blood counts in a 78-year-old woman.
A 78-year-old woman was evaluated in the emergency department with fever, chills, lethargy, fatigue, and confusion. Her maximum temperature was 100.6°F. Although her symptoms initially raised concern for sepsis, additional findings suggested a tick-borne infection.
Coinfection with Babesia and Anaplasma phagocytophilum is well recognized in areas where blacklegged ticks (Ixodes scapularis) are common because both organisms are transmitted by the same tick. Patients with coinfection may have overlapping clinical findings and require treatment directed against both organisms.
For a broader overview of tick-borne coinfections, see Tick-Borne Coinfections.
Her blood tests were markedly abnormal and revealed:
- Anemia (hemoglobin fell from 10.5 g/dL to 8 g/dL)
- Leukopenia (white blood cell count fell from 5.0 × 109/L to 2.6 × 109/L)
- Thrombocytopenia (platelet count dropped to 39 × 109/L)
These laboratory abnormalities raised concern for multiple tick-borne infections rather than Lyme disease alone.
[bctt tweet=”A combination of the tick-borne diseases Babesia and Anaplasmosis can lead to confusion.” username=”DrDanielCameron”]
The treating physicians initially considered sepsis. Sepsis is a life-threatening condition caused by an overwhelming response to infection that can lead to organ dysfunction and death if not recognized promptly.
Anaplasmosis and babesiosis coinfection
The patient also reported multiple tick bites, increasing suspicion for a tick-borne illness.
Microscopic examination of her peripheral blood smear revealed parasites inside red blood cells, confirming babesiosis. Babesia is a protozoan parasite that infects red blood cells and commonly causes hemolytic anemia, particularly in older adults or individuals with weakened immune systems.
The physicians started treatment with atovaquone and azithromycin, the standard oral regimen for most cases of babesiosis.
However, her severe leukopenia and thrombocytopenia suggested that another tick-borne infection might also be present. These findings are commonly seen with anaplasmosis, a bacterial infection caused by Anaplasma phagocytophilum.
Because atovaquone and azithromycin do not treat anaplasmosis, the physicians added doxycycline. This decision was important because coinfection requires treatment directed against both organisms.
Laboratory testing later supported the diagnosis of both babesiosis and anaplasmosis. The authors reported positive IgM tests for both infections. However, interpretation of IgM testing—particularly for anaplasmosis—has limitations, and current diagnostic recommendations favor PCR during early illness or paired IgG antibody testing.
The woman’s cognitive function improved dramatically after two weeks of treatment, according to the authors.
What can we learn from this case?
- Anaplasmosis and babesiosis coinfection can cause confusion in older adults. Fever, lethargy, and altered mental status may be mistaken for sepsis or another serious infection.
- Laboratory abnormalities provide important diagnostic clues. Anemia, leukopenia, and thrombocytopenia should prompt clinicians to consider tick-borne coinfections, particularly in endemic areas.
- Babesiosis and anaplasmosis require different treatments. Atovaquone plus azithromycin is commonly used for babesiosis, while doxycycline is the treatment of choice for anaplasmosis. Patients with coinfection may require both regimens.
- Early recognition may improve outcomes. Prompt diagnosis and treatment led to rapid improvement in this patient’s mental status and blood abnormalities.
Questions raised by this case
- How often do older adults with tick-borne infections present primarily with confusion or altered mental status?
- If Babesia parasites had not been identified on the peripheral blood smear, would the patient have received timely treatment for babesiosis?
- Would the patient have recovered as quickly if anaplasmosis had not been considered and doxycycline had not been added?
- What should clinicians do when early laboratory testing is negative but clinical suspicion for tick-borne disease remains high?
- Can acute confusion caused by severe tick-borne infections contribute to long-term cognitive decline in vulnerable older adults?
Treating tick-borne disease in my practice
Every patient requires an individualized evaluation. In my practice, I order a broad range of laboratory studies to evaluate for tick-borne infections while also looking for other medical conditions that can produce similar symptoms. Consultation with specialists may also be appropriate depending on the clinical presentation.
Many patients with suspected Lyme disease have complex illnesses involving more than one tick-borne infection. This case illustrates why clinicians should remain alert for coinfections, especially when laboratory findings such as anemia, leukopenia, or thrombocytopenia are present.
If you would like a broader overview of babesiosis, visit Babesia and Lyme Disease.
Older adults may present differently than younger patients. Fever may be mild, while confusion, weakness, or falls may dominate the clinical picture. Recognizing these atypical presentations can help avoid delays in diagnosis and treatment.
Frequently Asked Questions
Can you have anaplasmosis and babesiosis at the same time?
Yes. Both infections are transmitted by the blacklegged tick (Ixodes scapularis), making coinfection possible after a single tick bite. Patients with coinfection may have more severe illness and require treatment directed against both organisms.
What is the difference between babesiosis and anaplasmosis?
Babesiosis is caused by a parasite that infects red blood cells and commonly causes anemia. Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum, which infects white blood cells and often causes leukopenia and thrombocytopenia. Because they respond to different antibiotics, distinguishing between the two infections is important.
Can anaplasmosis cause confusion?
Yes. Although fever, headache, and muscle aches are common symptoms, older adults may develop confusion or altered mental status, particularly when infection is severe or accompanied by other medical problems.
Can babesiosis cause anemia?
Yes. Babesia parasites invade and destroy red blood cells, which can lead to hemolytic anemia. Older adults, immunocompromised individuals, and patients without a spleen are at greater risk for severe disease.
Why were doxycycline, atovaquone, and azithromycin all used?
Each medication targets a different organism. Atovaquone plus azithromycin is commonly prescribed for babesiosis, while doxycycline is the recommended treatment for anaplasmosis. Patients with confirmed or strongly suspected coinfection may require treatment for both infections.
Clinical Takeaway
This case illustrates how anaplasmosis and babesiosis coinfection can present with fever, confusion, anemia, leukopenia, and thrombocytopenia in an older adult. Because both infections are transmitted by the same tick, clinicians should consider coinfection when laboratory abnormalities extend beyond those typically seen with Lyme disease alone.
Prompt recognition of babesiosis and anaplasmosis is important because each infection requires different antimicrobial therapy. Early diagnosis and appropriate treatment may improve outcomes, particularly in older adults who are at increased risk for severe disease.
Maintaining a high index of suspicion for tick-borne coinfections can prevent delayed diagnosis and improve recovery in patients with compatible symptoms and laboratory findings.
Related Articles
Learn more about the diagnosis and management of Lyme disease and tick-borne infections:
Lyme Disease Misdiagnosis
Persistent Lyme Disease
Why Lyme Disease Tests Can Miss the Diagnosis
Lyme Disease Symptoms Guide
References
- Paparone P, Paparone PW. Variable clinical presentations of babesiosis. Nurse Pract. 2018;43(10):48-54.
- Centers for Disease Control and Prevention. DPDx: Babesiosis.
- Centers for Disease Control and Prevention. About Anaplasmosis.
- Lantos PM, Rumbaugh J, Bockenstedt LK, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease. Clin Infect Dis. 2021;72(1):e1-e48.
- Krause PJ, Auwaerter PG, Bannuru RR, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA): 2020 Guideline on Diagnosis and Management of Babesiosis. Clin Infect Dis. 2021;72(2):e49-e64.
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, Dr. Cameron, for your dedication and consistently excellent commentary! Because of your pioneering efforts with these horrific tick-borne diseases, the medical community is slowly becoming more intelligent about our country’s virtual plague of Lyme and its co-infections! Please keep on fighting the ignorance that is still much too prevalent! Thank you!
Thank you.
Very common scenario. If also bitten by dog Dermacentor ticks, the patients might have three (3) tick borne infections, adding Rickettsias to the cocktail. Rickettsioses might add transient, reversible strokes or head CVA’s in these young and old tick-infected people. Many great imitator diseases occur in tick-endemic areas beyond Lyme and the borrelioses. Thank you, Dr Cameron!!!
It’s been said the standard Rx used for Babesia is 2X750 mg atovaquone and 500 mg Azithromycin. Yet, some specialists with the disease insist this is simply too low and virtually no patient has been cured with this routine.Moreover, some are recommending Coartem as being more effective than the 2 drugs mentioned,considerably so.
I have not come to the same conclusion for many of my patients. I often find Malarone, a prescription that contains 250 twice a day of atovaquone. I have not advised Coartem. Not everyone agrees.