What is the treatment for Babesiosis?

Treatment of Babesiosis

All patients with active babesiosis should be treated with antimicrobial therapy, with the preferred first-line treatment being a combination of either atovaquone plus azithromycin or clindamycin plus quinine for 7-10 days. 1

Diagnosis Criteria

Before initiating treatment, confirm active babesial infection by:

• Presence of viral infection-like symptoms (fever, chills, sweats, myalgia, arthralgia)
• Identification of babesial parasites in blood by smear evaluation or PCR amplification of babesial DNA 1

Treatment should not be given to:

• Asymptomatic individuals regardless of serologic test results
• Symptomatic patients with only antibody positivity but no parasites on smear or PCR 1

Treatment Algorithm

First-Line Treatment Options

1. Atovaquone plus Azithromycin (Preferred due to better tolerability) 1, 2

   • Adults:
     • Atovaquone: 750 mg orally every 12 hours
     • Azithromycin: 500-1000 mg on day 1, then 250 mg once daily thereafter
   • Children:
     • Atovaquone: 20 mg/kg every 12 hours (maximum 750 mg per dose)
     • Azithromycin: 10 mg/kg on day 1 (maximum 500 mg), then 5 mg/kg once daily

2. Clindamycin plus Quinine 1

   • Adults:
     • Clindamycin: 300-600 mg IV every 6 hours or 600 mg orally every 8 hours
     • Quinine: 650 mg orally every 6-8 hours
   • Children:
     • Clindamycin: 7-10 mg/kg every 6-8 hours (maximum 600 mg per dose)
     • Quinine: 8 mg/kg every 8 hours (maximum 650 mg per dose)

Special Considerations

• Severe Babesiosis: Use clindamycin plus quinine, with clindamycin administered intravenously 1
• Immunocompromised Patients: Consider higher doses of azithromycin (600-1000 mg per day) when using atovaquone combination 1

Adjunctive Therapy

Exchange Transfusion is indicated for patients with severe babesiosis characterized by:

• High-grade parasitemia (>10%)
• Significant hemolysis
• Renal, hepatic, or pulmonary compromise 1

Consult with an infectious diseases expert and hematologist for exchange transfusion decisions.

Monitoring and Follow-up

• Mild-to-moderate babesiosis: Clinical improvement should occur within 48 hours after starting therapy
• Severe babesiosis: Monitor hematocrit and percentage of parasitized erythrocytes daily or every other day until parasitemia decreases to <5% 1
• Complete resolution of symptoms should occur within 3 months of treatment initiation
• Some patients may have persistent low-grade parasitemia for months despite appropriate therapy 1

Treatment Efficacy and Adverse Effects

The atovaquone and azithromycin combination is associated with significantly fewer adverse effects (15% vs 72%) compared to clindamycin and quinine 2. Common adverse effects include:

• Atovaquone/Azithromycin: Diarrhea and rash (each in 8% of patients) 2
• Clindamycin/Quinine: Tinnitus (39%), diarrhea (33%), decreased hearing (28%), and other gastrointestinal upset 1, 2

Important Considerations

• Consider coinfection with Borrelia burgdorferi (Lyme disease) or Anaplasma phagocytophilum in patients with severe or persistent symptoms despite appropriate treatment 1
• Evaluate for underlying immunodeficiency (asplenia, malignancy, HIV) in patients with severe or prolonged disease 1
• Longer duration of therapy may be necessary for highly symptomatic or immunocompromised patients until parasitemia is cleared 1

Treatment Outcomes

Recent studies show improved outcomes with current treatment regimens, with mortality rates lower than historical controls 3. In clinical trials, both treatment regimens resulted in complete clearance of parasites and resolution of symptoms within 3-6 months 2.