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
• Possible to have co-infection with Lyme (same tick family)

Clinical Features

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

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

Diagnosis

• CBC
  • Often with depressed white count
• Peripheral Blood Smears
  • 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
• Electrolytes and renal function
• LFTs
  • Total bilirubin and haptoglobin values reflect the intensity of the infection (hemolysis)
• Lyme
• Urine - hemolysis
• CXR - rare but possible ARDS

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

See Also

• Tick Borne Illnesses

Sources

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