Key points
- Most asymptomatic patients do not require treatment.
- A 7- to 10-day course of two prescription medications is the standard treatment for ill immunocompetent patients.
- Patients with immunocompromise may require longer treatment courses.
Treatment options
For ill patients, treatment usually involves at least a 7- to 10-day course of two prescription medications; often the duration of treatment is longer in immunocompromised patients. The typical combinations are:
- atovaquone PLUS azithromycin (preferred)
- clindamycin PLUS quinine* (alternative)
The tables below are adapted from the 2020 IDSA Guideline on Diagnosis and Management of Babesiosis and list typical daily doses for adults.
Patients with mild to moderate disease in outpatient setting
Drug
Adult dosage (usually treat for at least 7 – 10 days)
Preferred
Atovaquone**
750 mg orally twice a day
along with
Azithromycin
On the first day, give 500 mg orally; on subsequent days, give 250 mg*** daily
Alternative
Clindamycin
600 mg orally 3 times a day
or
Quinine*
650 mg orally 3 times a day
Hospitalized patients with acute severe disease
Drug
Adult dosage (continue until symptoms subside)
Preferred
Atovaquone**
750 mg orally twice a day
along with
Azithromycin
500 mg intravenously daily***
Alternative
Clindamycin
600 mg intravenously 4 times a day
or
Quinine*
650 mg orally 3 times a day
After symptoms subside with either of the two regimens, the patient should be transitioned to all oral medications at the same doses as in the outpatient setting. Continue therapy to complete a total of 7 to 10 days of treatment.
*Parenteral quinidine is no longer available in the United States
**Administer with food, preferably a fatty meal, to increases absorption
***A higher dosage of azithromycin 1000 mg, followed by 500mg daily, has been used in immunocompromised patients and in patients with more severe disease
Additional considerations
In people with competent immune systems, usually most symptoms resolve and blood smears become negative during the standard 7-10 day treatment course. Fatigue and PCR positivity may persist for several weeks after treatment, but relapse is unusual.
For highly immunocompromised patients, treatment may be required for at least 6 consecutive weeks or longer. It may be necessary to start with a regimen recommended for hospitalized patients followed by a regimen recommended for ambulatory patients. Immunocompromised patients require close clinical and laboratory follow up. Peripheral blood smears should be obtained daily until parasitemia is <4%, with smears done at least weekly after that. Treatment should be continued until parasites are no longer detected on smears for 2 consecutive weeks. Limited data on treatment efficacy exist in immunocompromised patients with disease relapse. Some experts recommend alternative regimens such as atovaquone plus azithromycin plus clindamycin, atovaquone plus clindamycin, atovaquone/proguanil (Malarone) plus azithromycin, or atovaquone plus azithromycin plus clindamycin plus quinine (IDSA 2020).
Some patients*—including those with severe illness—might require or benefit from supportive care, such as:
- Antipyretics
- Vasopressors (if the blood pressure is low and unstable)
- Blood transfusions
- Exchange transfusions in which portions of a patient's blood or blood cells are replaced with transfused blood components (typically used with high-grade parasitemia (>10%) or moderate to high-grade parasitemia along with severe hemolytic anemia or decline in pulmonary, renal, or hepatic function)
- Mechanical ventilation
- Dialysis
* Krause PM, Auwaerter PG, RR Bannuru, et al. Clinical Practice Guidelines by the Infectious Disease Society of America (IDSA): 2020 Guideline on Diagnosis and Management of Babesiosis
Care precautions
Treatment in Pregnancy
Atovaquone is in Pregnancy Category C. Data on the use of atovaquone in pregnant women are limited, and the risk to the embryo-fetus is unknown. Because data are available about safe administration of quinine plus clindamycin during pregnancy, this drug combination, rather than atovaquone (plus azithromycin), generally is recommended for treatment of symptomatic babesiosis during pregnancy, unless the preferred medications are not available or tolerated.
Treatment During Lactation
It is not known whether atovaquone is excreted in breast milk. Atovaquone should be used with caution in women breastfeeding infants who weigh <5 kg.
Treatment in Pediatric Patients
Atovaquone has been used safely in children who weigh > 5 kg.
Azithromycin is in pregnancy category B. Data on the use of azithromycin in pregnant women are limited. Azithromycin may be used during pregnancy in those patients who will clearly benefit from the drug.
Treatment During Lactation
According to a case report, azithromycin was excreted in breast milk and the nursing infant did not have adverse effects. Azithromycin should be used with caution in breastfeeding women, although the risk to the exposed infant probably is low.
Treatment in Pediatric Patients
In controlled clinical trials for various bacterial infections, oral azithromycin has been safely administered to pediatric patients aged 6 months to 16 years. Anecdotal cases of babesiosis in children, including infants, have been safely treated with azithromycin plus atovaquone.
Treatment in Pregnancy
Clindamycin is in pregnancy category B. Data on the use of clindamycin in pregnant women are limited, although no congenital anomalies have been reported. Clindamycin may be used during pregnancy in those patients who will clearly benefit from the drug.
Pregnancy Category B: Either animal-reproduction studies have not demonstrated a fetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the first trimester (and there is no evidence of a risk in later trimesters).
Treatment During Lactation
Clindamycin is excreted in breast milk. The American Academy of Pediatrics classifies clindamycin as usually compatible with breastfeeding.
The parenteral form of clindamycin contains benzyl alcohol, which has been associated with a fatal "gasping syndrome" in premature infants.
Treatment in Pregnancy
The parenteral form of clindamycin contains benzyl alcohol, which has been associated with a fatal "gasping syndrome" in premature infants.