Babesiosis Treatment & Management

Updated: Jul 31, 2018
  • Author: Burke A Cunha, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Approach Considerations

Suspicion of babesiosis in a patient with a history of exposure in an endemic area, tick bite, fever, chills, and fatigue is crucial. Peripheral blood smear or immunologic testing (see Workup) is necessary to make the diagnosis. A complete blood count (CBC) count with differential is important for determining the severity of infection.

Patients with congenital or acquired asplenia should be expected to have severe or fulminant babesiosis. In patients with fever of unknown origin (FUO), consider babesiosis as a diagnosis if the patient lives in or has traveled to an endemic area or received a blood transfusion in the past. [20]

If the patient is otherwise healthy and asymptomatic, no treatment is required. Most of the otherwise healthy patients infected by B microti appear to have a mild illness and recover without specific chemotherapy; however, treatment is recommended for all diagnosed cases to prevent sequelae and potential transmission through blood donation.

Immediately start elderly, immunocompromised, or asplenic patients on a combination treatment regimen of intravenous (IV) clindamycin and oral quinine or IV atovaquone and IV azithromycin to avoid acute renal failure. Combination therapy with clindamycin and quinine or atovaquone and azithromycin is more effective than either atovaquone or azithromycin alone. Do not give quinine to pregnant patients.

Intubation and mechanical ventilation may be required for patients who develop respiratory distress or failure.


Pharmacologic Therapy

In asymptomatic patients with positive results from peripheral smears or polymerase chain reaction (PCR) testing, the studies should be repeated and a course of treatment started if parasitemia persists for more than 3 months. Additionally, patients who were initially treated may require repeat treatment if repeat smears or PCR assays are positive more than 3 months after initial therapy.

In symptomatic patients, antibiotic and antimalarial therapy should be started immediately after diagnosis to reduce the level of parasitemia. The standard treatment has been a combination of clindamycin (20 mg/kg/day for children; 300-600 mg IV or intramuscularly [IM] every 6 hour for adults) and oral quinine (25 mg/kg/day for children; 650 mg every 6-8 hours for adults) administered for 7-10 days. However, this regimen occasionally fails, and patients report frequent side effects, including tinnitus, impaired hearing, and diarrhea.

Consequently, a drug regimen consisting of atovaquone and azithromycin is now first-line treatment for mild-to-moderate disease and has been shown to be effective, especially when clindamycin and quinine fail.

In a prospective nonblinded randomized study, Krause et al found that atovaquone (750 mg every 12 hours) plus azithromycin (500 mg on day 1 and 250 mg/day thereafter) was as effective as clindamycin (600 mg every 8 hours) plus quinine (650 mg every 8 hours) in producing a clinical response and clearing parasitemia. [21] All patients were treated for 7 days. Adverse effects were reported by 15% of the atovaquone-azithromycin group and 72% of the clindamycin-quinine group.

The combination of clindamycin, doxycycline, and azithromycin was successfully used in a patient who was allergic to quinine.

A patient with acquired immune deficiency syndrome (AIDS) and babesiosis failed treatment with azithromycin and atovaquone followed by quinine and clindamycin. The addition of atovaquone-proguanil to the treatment regimen led to cure. [22]

One report listed 3 highly immunocompromised patients who received a subcurative course of azithromycin-atovaquone, which led to the development of resistance to this regimen. [23]

For patients with severe symptoms, clindamycin and quinine remain the first line of treatment. [1] Parasitemia may persist despite treatment with either of the drug regimens described above. In areas endemic for Lyme disease, physicians should consider treating for Lyme disease empirically.

Immunocompromised individuals who are infected by B microti are at risk for persistent relapsing illness. Such patients generally require antibabesial treatment for 6 weeks or longer to achieve cure, including 2 weeks after parasites are no longer detected on blood smears. [24]


Exchange Transfusion and Supportive Care

Exchange transfusion is employed in patients who are profoundly ill with high levels of parasitemia and hemolysis. In severe cases of babesiosis—as demonstrated by high parasitemia (>10%), significant hemolysis, or renal, hepatic, or pulmonary dysfunction—it may be lifesaving. When used concurrently with chemotherapy, exchange transfusion reduces the level of parasitemia and may remove toxic erythrocyte, babesial, or macrophage-produced factors.

Patients with severe babesiosis need to be hospitalized. In addition to receiving anti-Babesia treatment, they may require supportive care. Critically ill patients should be transferred to the intensive care unit (ICU). Patients with mild-to-moderate babesiosis who are discharged from the hospital should undergo the same laboratory tests as hospitalized patients.

Patients being treated for babesiosis should be monitored clinically, and serial blood smears should be obtained to document the degree of parasitemia and the effectiveness of therapy. Serial CBC counts may be obtained to assess the reticulocyte response and evaluate decrease in the hemolytic process. Be alert for the possibility of hemophagocytic syndrome.

Monitor the level of oxygenation, and watch for the development of respiratory complications after the initiation of treatment in patients who present with respiratory complaints. Respiratory distress may be due to endotoxin sensitivity; endotoxin release often results from medication-induced intraerythrocytic death of the parasites. Mechanical ventilation may be necessary in patients with severe disease.