Babesiosis

Background

• Spread by the deer tick (Ixodes scapularis)
  • People often unaware they are bitten
• Natural reservior is the white footed mouse
• Endemic in US, Europe, parts of Russia and China
  • Babesia Microti is pathogen in US

Symptoms

• Fever, hemolytic anemia, chills, thrombocytopenia, DIC
• More severe disease in immunocompromized patients (HIV, Elderly, Asplenic)

Diagnosis

• Peripheral blood smear
  • Shows intracellular parasites
    • Maltese Cross sign
  • May need large smear as parasitemia can be as low as 1%
  • Can often be confused for malaria parasites

Differential Diagnosis

Tick Borne Illnesses

• Babesiosis
• Colorado tick fever
• Ehrlichiosis
• Heartland virus
• Lyme
• Murine typhus
• Rocky mountain spotted fever
• Southern tick-associated rash illness (STARI)
• Tick paralysis
• Tularemia

Management

• 2 drug regimen for 7-10 days

Option 1

• Atovaquone (750mg BID) and Azithromycin (500-1000mg on first day, 250-1000mg on subsequent days)

Option 2

Clindamycin

• 600 mg PO q8h x 7-10 days
• Alt: 300-600mg IV q6h x 7-10 days
  • First Dose: 300-600mg IV x 1
• Give with Quinine (650mg TID); use IV for severe infections

Pediatrics

• Clindamycin 20 mg/kg/day for children and 25 mg/kg/day for children for 7-10 days

Treatment Failure

• Atovaquone 750 mg q12 and azithromycin 500 mg on day 1 and 250 mg/day x 7 days

See Also

• Tick Borne Illnesses

Sources

• CDC http://www.cdc.gov/parasites/babesiosis/