When Is Exchange Transfusion Recommended for Severe Babesiosis?
Severe babesiosis can become life-threatening.
Exchange transfusion may be needed for high parasitemia or organ dysfunction.
This case illustrates why some patients require repeat treatment.
Exchange transfusion is reserved for the most severe cases of babesiosis. Most patients improve with antimicrobial therapy alone, but individuals with high parasite levels, severe anemia, or organ dysfunction may require this life-saving procedure. The following case highlights how an immunocompromised patient with extremely high parasitemia ultimately required two exchange transfusions in addition to prolonged antimicrobial therapy.
Although the majority of Babesia infections respond to antimicrobial agents, Radcliffe and colleagues describe an unusual case in which a 73-year-old woman with severe Babesia microti infection required repeated exchange transfusions to achieve cure. Their report, Repeat exchange transfusion for treatment of severe babesiosis, illustrates the challenges of treating severe babesiosis in immunocompromised patients.
The woman ultimately required two exchange transfusions, along with prolonged anti-parasitic therapy, to successfully eradicate her Babesia microti infection.
When is exchange transfusion recommended?
The 2020 Infectious Diseases Society of America (IDSA) guideline recommends considering exchange transfusion for selected patients with severe babesiosis who have parasitemia greater than 10%, severe hemolytic anemia, or severe pulmonary, renal, or hepatic compromise. Exchange transfusion rapidly removes infected red blood cells while reducing the parasite burden and improving oxygen-carrying capacity.
The Centers for Disease Control and Prevention (CDC) similarly recommends specialist consultation for severe babesiosis because exchange transfusion may be lifesaving in carefully selected patients.
The patient described by Radcliffe and colleagues met several of these criteria. She presented with a parasitemia of 43%, anemia, hypotension, hypoxia, prior splenectomy, and immunosuppression. Her case illustrates why Babesia infection can be particularly dangerous in patients without a spleen or those receiving immune-suppressing medications.
Standard treatment for babesiosis
Most patients with babesiosis are treated with a combination of atovaquone plus azithromycin for 7 to 10 days. An alternative regimen of clindamycin plus quinine is generally reserved for selected patients with severe disease. Exchange transfusion is considered an adjunct to antimicrobial therapy rather than a replacement for it.
Patients who are immunocompromised, have persistent parasitemia, or experience relapsing infection often require substantially longer courses of antimicrobial therapy than otherwise healthy individuals.
Case report: Severe Babesia after camping in New Hampshire
Approximately one month after camping in New Hampshire, the woman developed malaise, headaches, weakness, anorexia, and nausea that persisted for four days. She did not recall a tick bite.
Her medical history included splenectomy, rheumatoid arthritis, and immunosuppressive therapy. “Her medical history was significant for longstanding rheumatoid arthritis treated with weekly etanercept and prior splenectomy for immune-mediated thrombocytopenia,” Radcliffe writes.
A peripheral blood smear demonstrated an extraordinary parasite burden of 43% along with anemia (hemoglobin 9.2 mg/dL). She was initially started on azithromycin and clindamycin before being transferred for higher-level care.
[bctt tweet=”Case report: Severe Babesia in a 73-year-old woman resolves after 2 exchange transfusions.” username=”DrDanielCameron”]
Following admission to the intensive care unit, she required intravenous fluids, vasopressors, and supplemental oxygen because of hypotension and hypoxia.
Her antimicrobial regimen was modified to include intravenous clindamycin, oral quinine sulfate, and oral doxycycline to empirically cover possible Lyme disease and anaplasmosis co-infection. Since Babesia microti is transmitted by the same Ixodes tick that spreads Lyme disease, co-infections may complicate diagnosis and treatment. Learn more about Lyme disease coinfections.
Why did this patient need two exchange transfusions?
On hospital day 1, the patient underwent a 12-unit red blood cell exchange transfusion. Her parasite burden fell dramatically from 43% to 7.6%.
Despite this initial improvement, parasitemia rebounded.
“Despite a post-exchange drop in parasitemia to 7.6%, it rebounded to 11.4% on hospital day 5 accompanied by new onset high fevers and hypoxia,” Radcliffe explains.
Because of worsening clinical status and increasing parasitemia, the patient underwent a second exchange transfusion on hospital day 5, lowering the parasite burden to 2.2%.
“She improved after a second exchange transfusion and ultimately resolved her infection after 12 weeks of anti-babesial antibiotics,” the authors report.
Extended antimicrobial therapy was continued because parasitemia remained measurable at 1.7% on hospital day 9 and less than 1% on hospital day 19.
“Antibiotics were discontinued as follows: atovaquone/proguanil at 61 days post-discharge, doxycycline at 72 days post-discharge, and azithromycin at 86 days post-discharge,” Radcliffe writes.
Who is at greatest risk for severe babesiosis?
Severe babesiosis occurs most often in older adults, patients who have undergone splenectomy, and individuals with impaired immune systems due to cancer, HIV infection, organ transplantation, autoimmune disease, or immunosuppressive medications.
These patients are more likely to develop severe hemolytic anemia, respiratory failure, kidney injury, persistent parasitemia, and relapse. The combination of splenectomy and immunosuppressive therapy made this patient particularly vulnerable.
For more information about the clinical presentation of this infection, see Babesia symptoms.
Exchange transfusion and prolonged antimicrobial therapy
Exchange transfusion does not eliminate the need for antimicrobial therapy. Instead, it rapidly reduces the number of infected red blood cells while antimicrobial agents eradicate the remaining parasites.
In this case, a single exchange transfusion was insufficient because parasitemia rebounded several days later. Two exchange transfusions combined with approximately 12 weeks of antimicrobial therapy were ultimately required to eradicate the infection.
The authors conclude, “Our present case is instructive because two exchange transfusions were necessary for cure despite a marked lowering of parasitemia after the first exchange transfusion and an extended anti-parasitic regimen.”
“These cases highlight the need to remain vigilant when managing babesiosis in highly immunocompromised patients.”
Future directions in babesiosis treatment
Investigational therapies such as tafenoquine have generated interest for the treatment of persistent or relapsing babesiosis, particularly in immunocompromised patients who remain parasitemic despite standard therapy. However, clinical evidence remains limited, and tafenoquine is not currently included as standard therapy in the IDSA babesiosis guideline. Additional studies are needed to clarify which patients, if any, may benefit from this approach. You can read more in our discussion of tafenoquine for Babesia.
Clinical Perspective
In my practice, most patients with babesiosis respond to antimicrobial therapy and never require exchange transfusion. However, I pay particularly close attention to patients who are elderly, immunocompromised, or have undergone splenectomy because they can deteriorate quickly and require more aggressive treatment. Early recognition and individualized management remain essential for achieving the best possible outcomes.
Frequently Asked Questions
When is exchange transfusion recommended for babesiosis?
The 2020 IDSA guideline recommends considering exchange transfusion for selected patients with severe babesiosis who have parasitemia greater than 10%, severe hemolytic anemia, or severe pulmonary, renal, or hepatic compromise. Clinical judgment is important because some patients with lower parasite burdens but significant organ dysfunction may also require aggressive management.
Can babesiosis be treated without exchange transfusion?
Yes. Most patients with babesiosis recover with antimicrobial therapy alone. The preferred treatment for uncomplicated disease is atovaquone plus azithromycin. Exchange transfusion is reserved for selected patients with severe disease and is used together with antimicrobial therapy rather than instead of it.
Why did this patient require two exchange transfusions?
Although the first exchange transfusion reduced parasitemia from 43% to 7.6%, parasite levels rebounded several days later. Because of persistent severe infection, hypoxia, and recurrent high parasitemia, a second exchange transfusion was required along with prolonged antimicrobial therapy.
Who is at highest risk for severe babesiosis?
Patients who are elderly, have undergone splenectomy, or are immunocompromised because of cancer, HIV infection, organ transplantation, autoimmune disease, or immunosuppressive medications are at greatest risk for severe babesiosis and its complications.
Can babesiosis relapse after treatment?
Yes. Relapse is uncommon in otherwise healthy individuals but may occur in immunocompromised patients. Persistent parasitemia can require prolonged antimicrobial therapy and close clinical follow-up.
Clinical Takeaway
Most patients with babesiosis improve with antimicrobial therapy and never require exchange transfusion. However, severe disease can develop rapidly in older adults, patients without a spleen, and those receiving immunosuppressive therapy.
This case demonstrates that exchange transfusion may be lifesaving when parasite burdens are very high or when severe anemia and organ dysfunction develop. It also highlights that a single exchange transfusion may not be sufficient in some immunocompromised patients, emphasizing the importance of close monitoring and individualized treatment.
Early recognition, prompt antimicrobial therapy, and timely consideration of exchange transfusion can improve outcomes in patients with severe babesiosis.
Related Articles
These related articles provide additional information on Babesia symptoms, treatment, and complications.
Case series looks at the complexity of Babesia
Case report: Various clinical presentations of Babesia
Healthy people may be unaware they are infected with Babesia
Babesia air hunger
Persistent Babesia infection
References
- 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):185-189.
- Centers for Disease Control and Prevention. Clinical Care of Babesiosis. Updated 2024.
- Bloch EM, Jacobs JW, Vannier E, Wormser GP, Gelfand JA, Sikand VK, et al. Guidance on the management of asymptomatic blood donors who test positive for Babesia. Clin Infect Dis. 2025.
- Amato M, Siller A, Schennach H. Babesiosis and Its Significance in Transfusion Medicine from a European Point of View. Transfus Med Hemother. 2025;53(1):23-43.
- Krause PJ. Human babesiosis. Int J Parasitol. 2019;49(2):165-174.
- Krause PJ, Gewurz BE, Hill D, Marty FM, Vannier E, Foppa IM, et al. Persistent and relapsing babesiosis in immunocompromised patients. Clin Infect Dis. 2008;46(3):370-376.
- Radcliffe C, Krause PJ, Grant M. Repeat exchange transfusion for treatment of severe babesiosis. Transfus Apher Sci. 2019;58:102671.
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
