What is the recommended treatment for Babesiosis?

Treatment of Babesiosis

The recommended first-line treatment for mild to moderate babesiosis is atovaquone 750 mg orally every 12 hours plus azithromycin 500-1000 mg orally on day 1, followed by 250 mg once daily for 7-10 days. 1

Treatment Algorithm Based on Disease Severity

Mild to Moderate Babesiosis

• First-line therapy: Atovaquone plus azithromycin
  • Adults: Atovaquone 750 mg orally every 12 hours plus azithromycin 500-1000 mg orally on day 1, followed by 250 mg once daily for 7-10 days 1
  • Children: Atovaquone 20 mg/kg every 12 hours (maximum 750 mg per dose) plus azithromycin 10 mg/kg on day 1 (maximum 500 mg), then 5 mg/kg once daily thereafter 2, 1
  • For immunocompromised patients: Higher doses of azithromycin (600-1000 mg per day) may be used 2

Severe Babesiosis

• First-line therapy: Clindamycin plus quinine
  • Adults: Clindamycin 300-600 mg IV every 6 hours (or 600 mg orally every 8 hours) plus quinine 650 mg orally every 6-8 hours 2, 1
  • Children: Clindamycin 7-10 mg/kg every 6-8 hours (maximum 600 mg per dose) plus quinine 8 mg/kg every 8 hours (maximum 650 mg per dose) 2
• Adjunctive therapy: Partial or complete RBC exchange transfusion for patients with:
  • High-grade parasitemia (>10%)
  • Significant hemolysis
  • Renal, hepatic, or pulmonary compromise 2, 1
  • Expert consultation with an infectious diseases specialist and hematologist is recommended 2

Monitoring and Follow-up

• In mild to moderate cases:

  • Clinical improvement should occur within 48 hours after starting therapy 2, 1
  • Symptoms should completely resolve within 3 months 2

• In severe cases:

  • Monitor hematocrit and percentage of parasitized erythrocytes daily or every other day until:
    • Clinical improvement occurs
    • Parasitemia decreases to <5% 2, 1

Special Considerations

Coinfections

• Consider possible coinfection with Borrelia burgdorferi (Lyme disease) or Anaplasma phagocytophilum in patients with:
  • Especially severe symptoms
  • Persistent symptoms despite appropriate antibabesial therapy 2, 1
• Treat coinfections with appropriate additional antimicrobial therapy

Immunocompromised Patients

• Higher risk for treatment failure and relapse 3
• May require longer duration of therapy until parasitemia is cleared 1
• Consider reducing immunosuppression when possible 3
• Monitor closely for development of drug resistance, especially to azithromycin-atovaquone 3

Evidence Comparison

The recommendation for atovaquone plus azithromycin as first-line therapy is supported by:

• A randomized trial showing equal efficacy to clindamycin plus quinine but with significantly fewer adverse effects (15% vs 72%) 4
• Adverse effects of atovaquone-azithromycin include diarrhea and rash (each in 8% of patients) 4
• Adverse effects of clindamycin-quinine include tinnitus (39%), diarrhea (33%), and decreased hearing (28%) 4

Pitfalls and Caveats

• Low parasitemia (<1% of erythrocytes) may make diagnosis challenging; consider PCR and serologic testing in addition to blood smears 5
• Some patients may have persistence of low-grade parasitemia for months after therapy 2
• Drug resistance to azithromycin-atovaquone can emerge in highly immunocompromised patients during treatment 3
• Treatment failures are more common in patients with:
  • Splenectomy
  • HIV infection
  • Concurrent corticosteroid therapy 1