section name header

Basics

Maged Muhammed

Isaac I. Bogoch

Eleftherios Mylonakis


BASICS


DESCRIPTION navigator

EPIDEMIOLOGY navigator

RISK FACTORS navigator

GENERAL PREVENTION navigator

PATHOPHYSIOLOGY navigator

The life cycle involves transmission of Babesia between vertebrate hosts and Ixodes ticks. Humans are "dead end" and "accidental" hosts as the primary contact points for B. microti are between white-footed mice and ticks. Although humans may become ill when infected, humans do not play a role in the transmission of infection. Ixodes ticks transmit the sporozoite to host blood. The sporozoites invade the erythrocytes and become trophozoites. The trophozoites replicate asexually by budding, yielding 2–4 merozoites. The merozoites disrupt RBCs and invade other RBCs leading to hemolysis and anemia.

ETIOLOGY navigator

COMMONLY ASSOCIATED CONDITIONS navigator


[Outline]

Diagnosis

DIAGNOSIS


HISTORY navigator

Patients may be asymptomatic or report the following symptoms:

PHYSICAL EXAM navigator

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests navigator

Follow Up & Special Considerations navigator

Imaging navigator

Usually imaging is not necessary in mild cases. Abdominal ultrasonography will confirm hepatomegaly or splenomegaly.

Pathological Findings navigator

Like malaria, Babesia appears as an intra-erythrocytic parasite. Babesia parasites can be visualized outside of red blood cells in heavy infection – this is not seen in malarial infections. Occasionally, Babesia parasites (in the intracellular merozoite phase) appear in tetrads, known as the "Maltese cross."

DIFFERENTIAL DIAGNOSIS navigator


[Outline]

Treatment

TREATMENT


MEDICATION

First Line navigator

For B. microti infection: 7–10 days of oral atovaquone 750 mg 2 times per day plus oral azithromycin 500–1,000 mg/day on day 1, followed by 250 mg/day afterwards.

Second Line navigator

For B. microti infection: Oral quinine 650 mg, 3 or 4 times a day plus oral clindamycin 600 mg 3 times a day for 7–10 days. Intravenous formulations can be used. Quinine and clindamycin are used in severe cases.

ADDITIONAL TREATMENT

General Measures navigator

Issues for Referral navigator

An infectious disease specialist should be involved if there are signs or symptoms of severe infection or infection in an immunocompromised host.

Additional Therapies navigator

Red blood cell exchange transfusions may be necessary in severe cases where parasitemia is high (>10%) or there are symptoms of shock/ARDS.


[Outline]

Ongoing Care

ONGOING-CARE


FOLLOW-UP RECOMMENDATIONS

Patient Monitoring navigator

Hospitalized patients should have a CBC and blood smear checked daily to monitor hemolysis, anemia, and parasite burden.

PATIENT EDUCATION navigator

Inform patients about risk factors for acquiring Babesia and take precautions to avoid re-infection.

COMPLICATIONS navigator


[Outline]

Codes

CODES


ICD9

088.82 Babesiosis

Clinical Pearls

References

  1. Vannier E, Gewurz BE, Krause PJ. Human babesiosis. Infect Dis Clin North Am 2008;22:469–488.
  2. Krause PJ, McKay K, Gadbaw J, et al. Increasing health burden of human babesiosis in endemic sites. Am J Trop Med Hyg 2003;68:431–436.
  3. Mylonakis E. When to suspect and how to monitor babesiosis. Am Fam Physician 2001;63:1969–1974.
  4. Wormser GP, Dattwyler RJ, Shapiro ED, et al. The clinical assessment, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis: Clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis 2006;43(9):1089–1134.
  5. Krause PJ, Gewurz BE, Hill D, et al. Persistent and relapsing babesiosis in immunocompromised patients. Clin Infect Dis 2008;46(3):370–376.