eMedicine Specialties > Emergency Medicine > Infectious Diseases

Babesiosis

Author: Tarlan Hedayati, MD, Instructor of Clinical Emergency Medicine, Director of Observation Unit, Director of Chest Pain Unit, Department of Emergency Medicine, Los Angeles County/University of Southern California Medical Center
Coauthor(s): Joseph Choi, MD, Resident Physician, Department of Emergency Medicine, LAC+USC Medical Center, Keck School of Medicine, University of Southern California
Contributor Information and Disclosures

Updated: Apr 28, 2009

Introduction

Background

Babesiosis is an intraerythrocytic parasitic infection caused by protozoa of the genus Babesia and transmitted through the bite of the Ixodes tick, the same vector responsible for transmission of Lyme disease. While most cases are tick-borne, transfusion and transplacental transmission have been reported. In the United States, babesiosis is usually an asymptomatic infection in healthy individuals. Several groups of patients become symptomatic, and, within these subpopulations, significant morbidity and mortality occur. The disease most severely affects patients who are elderly, immunocompromised, or asplenic. Among those symptomatically infected, the mortality rate is 10% in the United States and 50% in Europe.

Pathophysiology

Babesiosis is a zoonotic disease maintained by the interaction of tick vectors, transport hosts, and animal reservoirs. The primary vectors of the parasite are ticks of the genus Ixodes. In the United States, the black-legged tick, Ixodes scapularis (also known as Ixodes dammini) is the primary vector for the parasite; in Europe, Ixodes ricinus appears to be the primary tick vector. In each location, the Ixodes tick vector for Babesia is the same vector that locally transmits Borrelia burgdorferi, the agent implicated in Lyme disease.

<EM>Ixodes scapularis</EM>, tick vector for babes...

Ixodes scapularis, tick vector for babesiosis. Courtesy of the Centers for Disease Control and Prevention.

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<EM>Ixodes scapularis</EM>, tick vector for babes...

Ixodes scapularis, tick vector for babesiosis. Courtesy of the Centers for Disease Control and Prevention.


The primary US animal reservoir is the white-footed mouse, Peromyscus leucopus. Additionally, white-tailed deer serve as transport hosts for the adult tick vector, I scapularis. In Europe, the primary animal reservoir is cattle. 

The Ixodid ticks ingest Babesia during feeding from the host, multiply the protozoa in their gut wall, and concentrate it in their salivary glands. The tick inoculates a new host when feeding again. The parasite then infects red blood cells (RBCs) and differentiated and undifferentiated trophozoites are produced. The former produce 2-4 merozoites that disrupt the RBC and go on to invade other RBCs. This leads to hemolytic anemia, thrombocytopenia, and atypical lymphocyte formation. Alterations in RBC membranes cause decreased conformability and increased red cell adherence, which can lead to development of noncardiac pulmonary edema and acute respiratory distress syndrome (ARDS) among those severely affected.1

Peripheral smear showing babesiosis.

Peripheral smear showing babesiosis.

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Peripheral smear showing babesiosis.

Peripheral smear showing babesiosis.


Frequency

United States

The first US case of babesiosis was reported on Nantucket Island in 1966. An increasing trend over the past 30 years may be the result of restocking of the deer population, curtailment of hunting, and an increase in outdoor recreational activities. Between 1968 and 1993, more than 450 cases of Babesia infections were confirmed in the United States. However, the actual prevalence of this disease is unknown because most infected patients are asymptomatic.

International

The first case of human babesiosis was reported in 1957 from the former Yugoslavia in an asplenic farmer. Approximately 40 cases have been reported since then, mostly in Ireland, the United Kingdom, and France. Sporadic case reports of babesiosis in Japan, Korea, China, Mexico, South Africa, and Egypt have also been documented.

Mortality/Morbidity

Babesiosis exists as a spectrum of disease in 3 distinct groups: (1) asymptomatic infection, (2) a mild/moderate viral-like syndrome, and (3) severe disease with a fulminant course resulting in death or persistent relapsing course.1

The US mortality rate is significant.

  • Twenty-five percent of adults and 50% of children infected with babesiosis are asymptomatic and/or improve spontaneously without treatment.
  • Fewer than 10% of patients with babesiosis have died in the United States, mostly composed of elderly or asplenic patients.
  • Deaths have been reported from transfusion-transmitted babesiosis within the immunocompromised population in areas where Babesia infection is not endemic.2
  • Approximately 20% of patients with babesiosis are co-infected with Lyme disease. These patients experience more severe symptoms for a longer duration than those with either disease alone.

In Europe, babesiosis is a life-threatening disease.

  • Fifty-three percent of infected patients become comatose and die.
  • Eighty-three percent of infected patients are asplenic.

Race

Babesiosis has no predilection for race.

Sex

The male-to-female ratio is about 1:1.

Age

Babesiosis affects all age groups with similar frequency; however, patients older than 50 years are at increased risk for severe infection and death.

Clinical

History

Patients report a history of travel to an endemic area between the months of May and September. This is the period during which the Ixodes tick is in its infectious nymph stage; however, most do not recall the tick bite. The incubation period is between 1 and 4 weeks. The signs and symptoms mimic malaria and range in severity from asymptomatic to septic shock.

  • Symptoms

    • Generalized weakness
    • Fatigue
    • Depression
    • Fever
    • Anorexia and weight loss
    • CNS - Headache, photophobia, neck stiffness, altered sensorium
    • Pulmonary - Cough, shortness of breath
    • GI - Nausea, vomiting, abdominal pain
    • Musculoskeletal - Arthralgia and myalgia
    • Renal - Dark urine

Physical

Physical examination findings of babesiosis can include the following:

  • Fever
  • Rigors
  • Diaphoresis
  • Altered mental status
  • Renal insufficiency/failure
  • Pulmonary edema
  • Hepatosplenomegaly
  • Spontaneous splenic rupture3
  • Jaundice
  • Shock

Causes

More than 100 species of Babesia exist, but only a small number of species are known to be responsible for the majority of symptomatic disease. The causative agent of babesiosis varies according to geographic region.

  • In the United States, human infection with Babesia species is primarily due to Babesia microti, found mostly in northeastern and midwestern states. A few cases have been reported in Missouri, California, and Washington and are found to be caused by Babesia -like agents named after their geographic location, MO1 (Missouri), CA-1 (California), and WA-1 (Washington).
  • In Europe, the causative agent of babesiosis is typically Babesia divergens, though B microti and B microti -like agents have been identified.
  • Several reported cases of infection via blood transfusions from donors who lived in or traveled to an endemic area have been documented. All of these cases have occurred in the United States with the exception of one patient in Canada (acquired from a donor who became infected while in the United States) and one in Japan. The rate of acquiring B microti from a unit of packed red cells has been estimated to be 1 in 600-1800 in endemic areas.
  • Case reports of transplacental/perinatal transmission have been documented.

More on Babesiosis

Overview: Babesiosis
Differential Diagnoses & Workup: Babesiosis
Treatment & Medication: Babesiosis
Follow-up: Babesiosis
Multimedia: Babesiosis
References
Further Reading
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References

  1. Vannier E, Gewurz BE, Krause PJ. Human babesiosis. Infect Dis Clin North Am. Sep 2008;22(3):469-88, viii-ix. [Medline].

  2. Gubernot DM, Lucey CT, Lee KC, Conley GB, Holness LG, Wise RP. Babesia infection through blood transfusions: reports received by the US Food and Drug Administration, 1997-2007. Clin Infect Dis. Jan 1 2009;48(1):25-30. [Medline].

  3. Froberg MK, Dannen D, Bernier N, Shieh WJ, Guarner J, Zaki S. Case report: spontaneous splenic rupture during acute parasitemia of Babesia microti. Ann Clin Lab Sci. Autumn 2008;38(4):390-2. [Medline].

  4. Cunha BA, Cohen YZ, McDermott B. Fever of unknown origin (FUO) due to babesiosis in a immunocompetent host. Heart Lung. Nov-Dec 2008;37(6):481-4. [Medline].

  5. Berry A, Morassin B, Kamar N, Magnaval JF. Clinical picture: human babesiosis. Lancet. Feb 3 2001;357(9253):341. [Medline].

  6. Boustani MR, Gelfand JA. Babesiosis. Clin Infect Dis. Apr 1996;22(4):611-5. [Medline].

  7. Boustani MR, Lepore TJ, Gelfand JA, Lazarus DS. Acute respiratory failure in patients treated for babesiosis. Am J Respir Crit Care Med. Jun 1994;149(6):1689-91. [Medline].

  8. Brasseur P, Lecoublet S, Kapel N, Favennec L, Ballet JJ. Quinine in the treatment of Babesia divergens infections in humans. Eur J Clin Microbiol Infect Dis. Oct 1996;15:840-841. [Medline].

  9. Dobroszycki J, Herwaldt BL, Boctor F, et al. A cluster of transfusion-associated babesiosis cases traced to a single asymptomatic donor. JAMA. Mar 10 1999;281(10):927-30. [Medline].

  10. Feder HM, Lawlor M, Krause PJ. Babesiosis in pregnancy. N Engl J Med. Jul 10 2003;349(2):195-6. [Medline].

  11. Froberg MK, Dannen D, Bakken JS. Babesiosis and HIV. Lancet. Feb 28 2004;363(9410):704. [Medline].

  12. Gorenflot A, Moubri K, Precigout E, Carcy B, Schetters TP. Human babesiosis. Ann Trop Med Parasitol. Jun 1998;92(4):489-501. [Medline].

  13. Gratz NG. The vector-borne human infections of Europe: their distribution and burden on human health. WHO; 2004. 1-154. [Full Text].

  14. Gupta P, Hurley RW, Helseth PH, Goodman JL, Hammerschmidt DE. Pancytopenia due to hemophagocytic syndrome as the presenting manifestation of babesiosis. Am J Hematol. Sep 1995;50(1):60-2. [Medline].

  15. Gutman JD, Kotton CN, Kratz A. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 29-2003. A 60-year-old man with fever, rigors, and sweats. N Engl J Med. Sep 18 2003;349(12):1168-75. [Medline].

  16. Horowitz ML, Coletta F, Fein AM. Delayed onset adult respiratory distress syndrome in babesiosis. Chest. Oct 1994;106(4):1299-301. [Medline].

  17. Krause PJ. Babesiosis. Med Clin North Am. Mar 2002;86(2):361-73. [Medline].

  18. Krause PJ, Lepore T, Sikand VK, et al. Atovaquone and azithromycin for the treatment of babesiosis. N Engl J Med. Nov 16 2000;343(20):1454-8. [Medline].

  19. Krause PJ, Telford SR 3rd, Pollack RJ, et al. Babesiosis: an underdiagnosed disease of children. Pediatrics. Jun 1992;89(6 Pt 1):1045-8. [Medline].

  20. Krause PJ, Telford SR, Spielman A, et al. Concurrent Lyme disease and babesiosis. Evidence for increased severity and duration of illness. JAMA. Jun 5 1996;275(21):1657-60. [Medline].

  21. Leiby DA. Babesiosis and blood transfusion: flying under the radar. Vox Sang. Feb 2006;90(3):157-165. [Medline].

  22. Leiby DA, Chung APS, Gill JE, et al. Demonstrable parasitemia among Connecticut blood donors with antibodies to Babesia microti. Transfusion. Nov 2005;45:1804-1810. [Medline].

  23. Mylonakis E. When to suspect and how to monitor babesiosis. Am Fam Physician. May 15 2001;63(10):1969-74. [Medline].

  24. Perdrizet GA, Olson NH, Krause PJ, Banever GT, Spielman A, Cable RG. Babesiosis in a renal transplant recipient acquired through blood transfusion. Transplantation. Jul 15 2000;70(1):205-8. [Medline].

  25. Persing DH, Herwaldt BL, Glaser C, et al. Infection with a babesia-like organism in northern California. N Engl J Med. Feb 2 1995;332(5):298-303. [Medline].

  26. Pruthi RK, Marshall WF, Wiltsie JC, Persing DH. Human babesiosis. Mayo Clin Proc. Sep 1995;70(9):853-62. [Medline].

  27. Ryan R, Krause PJ, Radolf J, et al. Diagnosis of babesiosis using an immunoblot serologic test. Clin Diagn Lab Immunol. Nov 2001;8(6):1177-80. [Medline].

  28. Shoemaker RC, Hudnell HK, House DE, Van Kempen A, Pakes GE, COL40155 Study Team. Atovaquone plus cholestyramine in patients coinfected with Babesia microti and Borrelia burgdorferi refractory to other treatment. Adv Ther. Jan-Feb 2006;23(1):1-11. [Medline].

  29. Slovut DP, Benedetti E, Matas AJ. Babesiosis and hemophagocytic syndrome in an asplenic renal transplant recipient. Transplantation. Aug 27 1996;62(4):537-9. [Medline].

  30. Spach DH, Liles WC, Campbell GL, Quick RE, Anderson DE Jr, Fritsche TR. Tick-borne diseases in the United States. N Engl J Med. Sep 23 1993;329(13):936-47. [Medline].

  31. Weinberg GA. Laboratory diagnosis of ehrlichiosis and babesiosis. Pediatr Infect Dis J. Apr 2001;20(4):435-7. [Medline].

  32. Weiss LM, Wittner M, Tanowitz HB. The treatment of babesiosis. N Engl J Med. Mar 8 2001;344(10):773. [Medline].

  33. Wittner M, Lederman J, Tanowitz HB, Rosenbaum GS, Weiss LM. Atovaquone in the treatment of Babesia microti infections in hamsters. Am J Trop Med Hyg. Aug 1996;55(2):219-22. [Medline].

  34. 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. Nov 1 2006;43(9):1089-134. Epub 2006 Oct 2. [Medline].

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Further Reading

Clinical guidelines

Infectious Diseases Society of America practice guidelines for clinical assessment, treatment and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis. Wormser GP, Dattwyler RJ, Shapiro ED, Halperin JJ, Steere AC, Klempner MS, Krause PJ, Bakken JS, Strle F, Stanek G, Bockenstedt L, Fish D, Dumler JS, Nadelman RB. 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 Nov 1;43(9):1089-134. PubMed

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Keywords

babesiosis, Babesia species, Ixodes tick, parasitic infection, intraerythrocytic parasitic infection, tick bite, hemolytic anemia, thrombocytopenia, atypical lymphocyte formation, acute respiratory distress syndrome, ARDS, Lyme disease, Ixodes scapularis, white-tailed deer, white-footed mouse, Peromyscus leucopus, adult tick vector

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Contributor Information and Disclosures

Author

Tarlan Hedayati, MD, Instructor of Clinical Emergency Medicine, Director of Observation Unit, Director of Chest Pain Unit, Department of Emergency Medicine, Los Angeles County/University of Southern California Medical Center
Tarlan Hedayati, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Joseph Choi, MD, Resident Physician, Department of Emergency Medicine, LAC+USC Medical Center, Keck School of Medicine, University of Southern California
Joseph Choi, MD is a member of the following medical societies: American Academy of Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Edward Bessman, MD, Chairman, Department of Emergency Medicine, John Hopkins Bayview Medical Center; Assistant Professor, Department of Emergency Medicine, Johns Hopkins University
Edward Bessman, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Barry J Sheridan, DO, Chief, Department of Emergency Medical Services, Brooke Army Medical Center
Barry J Sheridan, DO is a member of the following medical societies: American Academy of Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: WebMD Salary Employment

 
 
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