What is the recommended treatment for babesiosis?

Treatment of Babesiosis

The recommended first-line treatment for babesiosis is a 7-10 day course of either atovaquone plus azithromycin or clindamycin plus quinine, with atovaquone plus azithromycin preferred for mild to moderate cases due to better tolerability. 1

Diagnosis Criteria

Before initiating treatment, confirm active babesial infection by:

• Presence of viral infection-like symptoms
• Identification of babesial parasites in blood by smear evaluation or PCR amplification of babesial DNA 1

Treatment should not be initiated based on seropositivity alone or in asymptomatic individuals, regardless of test results 1.

Treatment Algorithm

Mild to Moderate Babesiosis

• First-line regimen: Atovaquone plus azithromycin for 7-10 days 1
  • Adult dosing:
    • Atovaquone 750 mg orally every 12 hours
    • Azithromycin 500-1000 mg orally on day 1, then 250 mg once daily thereafter 1
  • Pediatric dosing:
    • 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 thereafter 1

Severe Babesiosis

• First-line regimen: Clindamycin plus quinine for 7-10 days 1
  • Adult dosing:
    • Clindamycin 300-600 mg IV every 6 hours (or 600 mg orally every 8 hours)
    • Quinine 650 mg orally every 6-8 hours 1, 2
  • Pediatric dosing:
    • 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) 1

Special Populations

• Immunocompromised patients: Consider higher doses of azithromycin (600-1000 mg per day) when using the atovaquone combination 1
• Patients with high parasitemia (>10%), significant hemolysis, or organ compromise: Add exchange transfusion to antimicrobial therapy 1

Adjunctive Therapy

Exchange Transfusion

• Indications:
  • High-grade parasitemia (>10%)
  • Significant hemolysis
  • Renal, hepatic, or pulmonary compromise 1
• Implementation: Consult with infectious disease specialist and hematologist 1

Monitoring and Follow-up

• Mild-to-moderate cases: Clinical improvement should occur within 48 hours after starting therapy 1
• Severe cases: Monitor hematocrit and percentage of parasitized erythrocytes daily or every other day until improvement and parasitemia decreases to <5% 1
• Complete symptom resolution should occur within 3 months of initiating therapy 1

Treatment Challenges and Pitfalls

Side Effects

• Clindamycin plus quinine: Associated with significant adverse effects (tinnitus, vertigo, gastrointestinal upset) in approximately 75% of patients 1, 3
• Atovaquone plus azithromycin: Better tolerated with adverse effects in only about 15% of patients 1, 3

Treatment Failures

• More common in patients with:
  • Splenectomy
  • HIV infection
  • Concurrent corticosteroid therapy 1
• Consider longer duration of therapy in highly symptomatic patients until parasitemia is cleared 1

Coinfections

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

Emerging Considerations

• Increasing incidence worldwide and risk of transfusion-transmitted infection make babesiosis a growing public health concern 4, 5
• Research is ongoing for new therapeutic agents that target Babesia through novel mechanisms to overcome potential resistance to current treatments 5

Human babesiosis remains a potentially life-threatening infection that requires prompt recognition and appropriate treatment to reduce morbidity and mortality, especially in immunocompromised and older patients 6.