Lyme Disease, Babesiosis, and Anaplasmosis in a 74-Year-Old Woman

One patient was diagnosed with three tick-borne infections
Severe babesiosis required two red blood cell exchanges
Coinfections may complicate diagnosis and treatment

Welcome to an Inside Lyme case study. One of the best ways to understand tick-borne diseases is by reviewing actual cases. In this episode, I discuss a critically ill 74-year-old woman diagnosed with babesiosis, Lyme disease, and anaplasmosis.

The case was described by Kumar and colleagues in a 2019 report published in Cureus.

A critically ill 74-year-old woman

The woman was an avid gardener with chronic obstructive pulmonary disease (COPD), hypertension, and a history of smoking. She reported one week of worsening shortness of breath, fatigue, and a productive cough.

She did not recall a tick bite, fever, rash, joint pain, or muscle pain.

When she arrived at the hospital, she was hypotensive, tachycardic, lethargic, pale, and in respiratory distress. Because pneumonia was initially suspected, she was treated with ceftriaxone and azithromycin.

Blood smear reveals severe babesiosis

A peripheral blood smear showed parasites inside her red blood cells that were consistent with Babesia. The parasite burden was 9.04%, meaning that approximately 9% of the examined red blood cells were infected.

Babesiosis is caused by a parasite transmitted by certain Ixodes ticks, including the blacklegged tick that also transmits the bacterium responsible for Lyme disease.

The patient had evidence of hemolytic anemia and severe thrombocytopenia. Her hemoglobin had fallen from a baseline of approximately 15 g/dL to 9.9 g/dL, and her platelet count was 34,000.

The doctors treated her with atovaquone and azithromycin for babesiosis. Atovaquone is marketed under the brand name Mepron in the United States. Doxycycline was added empirically because of concern for Lyme disease or another tick-borne coinfection.

Shock and respiratory distress

The woman remained hypotensive despite intravenous fluids and required norepinephrine to support her blood pressure. Positive-pressure ventilation was used because of her respiratory distress.

Because of the severity of the illness and the high parasite burden, the doctors performed erythrocytapheresis, also known as red blood cell exchange.

During this procedure, infected red blood cells are removed and replaced with donor red blood cells. The procedure can rapidly reduce the parasite burden while also removing damaged red cells and improving the blood’s oxygen-carrying capacity.

The parasite burden decreased after the first exchange but remained high. The published report contains a numerical inconsistency: its abstract reports 6.54% parasitemia after the first exchange, while the detailed case presentation reports 5.54%.

Because the patient remained in shock and developed acute kidney injury, the doctors performed a second red blood cell exchange. After the second procedure, parasitemia fell to 1.75%.

The case authors attributed her worsening kidney function to pigment-induced nephropathy associated with hemolysis.

Testing suggests two additional tick-borne infections

The patient’s Lyme IgM immunoblot was positive, while her Lyme IgG immunoblot was negative.

Testing for anaplasmosis showed an IgG antibody titer greater than 1:1024 and an IgM titer of 1:80. The authors interpreted these results as evidence of recent or current anaplasmosis.

Based on the blood smear, parasite burden, Lyme serology, and Anaplasma antibody results, the authors reported concurrent babesiosis, Lyme disease, and anaplasmosis.

Serologic results must always be interpreted in the context of the patient’s symptoms, exposure history, timing of illness, and other laboratory findings. A positive antibody test does not always establish that an infection is responsible for every feature of an illness.

Treatment changed as her illness progressed

Clindamycin was added after the patient remained in shock following the first red blood cell exchange. Atovaquone and azithromycin were later discontinued, and quinine was added.

The final antimicrobial regimen included clindamycin, quinine, and doxycycline.

The patient’s blood pressure and respiratory condition improved. She no longer required medication to support her blood pressure, and her blood counts and kidney and liver function returned to normal after 14 days of antimicrobial treatment.

Atovaquone plus azithromycin is now generally the preferred combination for babesiosis because it is typically better tolerated. Clindamycin plus quinine is an alternative regimen that may be considered in selected severe or difficult-to-treat cases.

One tick may carry multiple pathogens

Studies have identified multiple disease-causing organisms in individual ticks. A person may therefore acquire more than one tick-borne infection following a single tick exposure.

Kumar and colleagues noted that infection with three pathogens is considered uncommon. Nevertheless, clinicians should consider coinfections when a patient has an unusually severe presentation, unexplained laboratory abnormalities, or an incomplete response to the initial treatment.

In my clinical practice, I have also evaluated patients with evidence suggesting exposure to or infection with multiple tick-borne pathogens, although many such clinical experiences are never formally published.

For a more detailed discussion of this case and another published triple-infection case, see One Tick Bite Caused Three Tick-Borne Diseases.

Testing for Babesia and Anaplasma

A peripheral blood smear can directly demonstrate Babesia parasites inside red blood cells. However, a smear may be negative when the parasite burden is low. PCR testing may provide additional evidence when babesiosis remains clinically suspected despite a negative smear.

Testing for anaplasmosis can also be challenging. During the early stage of illness, morulae may occasionally be seen inside granulocytes, which are a type of white blood cell. Anaplasma organisms are not typically identified inside red blood cells.

A blood smear has limited sensitivity for anaplasmosis and should not be used as the sole diagnostic test. PCR is most useful early in the illness, while properly timed acute and convalescent antibody testing may provide additional evidence.

Treatment duration depends on the patient

The authors discussed prolonged Babesia treatment for certain immunocompromised patients at risk of persistent or relapsing infection. They cited treatment lasting at least six weeks, including two weeks after parasites were no longer visible on blood smear.

This prolonged course does not apply routinely to every patient with babesiosis. Treatment duration depends on illness severity, immune status, clinical response, laboratory findings, and whether parasites remain detectable.

What can we learn from this case?

1. Tick-borne infections should remain in the differential diagnosis even when a patient has underlying medical conditions or does not recall a tick bite or rash.
2. More than one tick-borne infection may occur at the same time.
3. Severe babesiosis may cause hemolytic anemia, thrombocytopenia, shock, kidney injury, and respiratory complications.
4. Patients with severe illness or an atypical response to treatment may require evaluation for additional tick-borne infections.
5. Selected patients with severe babesiosis may require red blood cell exchange in addition to antimicrobial treatment.

What questions does this case raise?

1. Would babesiosis have been recognized if parasites had not been visible on the initial blood smear?
2. How should clinicians interpret positive Lyme and Anaplasma antibody tests in a patient whose most prominent findings are explained by severe babesiosis?
3. When should red blood cell exchange be performed in a patient with severe babesiosis and organ dysfunction?
4. What treatment combination and duration are most appropriate for patients with multiple tick-borne infections?

Treating Multiple Tick-Borne Infections

Clinicians need the skills to recognize and treat patients who may have more than one tick-borne infection. No single test can reliably answer every diagnostic question or always determine when a tick-borne infection has resolved.

This case reminds clinicians to consider coinfections when an illness is unusually severe, laboratory abnormalities are disproportionate, or the patient does not improve as expected. Treatment decisions must be individualized according to the infections under consideration, the strength of the diagnostic evidence, the severity of illness, and the patient’s response to therapy.

This article describes a published case report and is intended for educational purposes. It is not medical advice and does not establish that the same diagnostic or treatment approach is appropriate for every patient.

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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