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babesiosis

Etiology: - protozoan infection with Babesia species Epidemiology: 1) Babesia microti in northeastern & midwestern states a) Nantucket Island, Cape Cod, Maine b) transmitted by: 1] Ixodes scapularis, the same tick that transmits Lyme disease & Rocky Mountain spotted fever 2] Ixodes dammini 2) Babesia species (WA-1) in western states a) Northern California b) transmitted by western black-legged tick Ixodes pacificus 3) Babesia divergens in Euorope a) canine parasite b) transmitted by Ixodes ricinus 4) transfusion-related cases in USA [4] Pathology: 1) parasitic infection of erythrocytes 2) parasitemia varies from 1-80% of erythrocytes 3) parasites multiply within erythrocytes by schizogony 4) co-infection with Borrelia burgdorferi &/or Ehrlichia 5) hemolytic anemia Clinical manifestations: 1) generally asymptomatic 2) mild febrile flu-like illness - fever, mylagia, headache, fatigue - may occur 1 week to 6 months after transfusion, median onset 37 days 2) severe infections in asplenic & immunocompromised patients including: a) elderly b) patients with malignancy c) patients receiving immunosupressive agent(s) 3) malarial-like symptoms a) fever, chills, sweats b) malaise, fatigue c) myalgias d) headache f) hemolytic anemia g) kidney injury [1] h) no recognizable periodicity 4) jaundice, hepatosplenomegaly Laboratory: 1) findings compatable with hemolytic anemia a) complete blood count (CBC): anemia, thrombocytopenia b) reticulocyte count: elevated c) serum lactate dehydrogenase elevated d) serum alkaline phosphatase elevated e) serum ALT & serum AST elevated f) serum unconjugated bilirubin elevated g) serum haptoglobin diminished h) urinaylsis: hemoglobinuria 2) Wright-stained peripheral blood smear obtained during a chill [7] a) trophozoites appear as multiple ring forms within RBC that may form a tetrad (maltese cross) (images) [10,11] b) no large growing trophozoites or gametocytes c) no hemazoin pigment present in Plasmodium-infected cells d) schistocytes d) sensitivity depends on level of parasitemia [1] 3) Babesia serology: a) serology for malaria is negative in babesiosis b) patients with malaria may cross-react with babesia serology c) fluorescent antibody (IFA) 4) Babasia DNA, Babesia rRNA a) method of choice for diagnosis [1] b) repeat Babesia microti DNA after 3 months to assess parasite clearance (no need to treat/retreat) [1] 5) see ARUP consult [5] Complications: 1) acute respiratory failure, respiratory distress syndrome 2) acute renal failure 3) disseminated intravascular coagulation (DIC) 4) splenic rupture 5) heart failure associated with severe anemia [1] 6) death Management: 1) infections are generally self-limited in patients with intact spleens without treatment - monitoring for resolution of parasitemia recommended for 3 months [1] 2) pharmaceutical agents - atovaquone 750 mg BID plus azithromycin 500-1000 mg QD - clindamycin 600 mg PO TID or 1.2 g IV BID - quinine sulfate 650 mg PO TID - either agent in patients with normal immunity, both in immunocompromised patients - ICU admission: clindamycin + quinine - duration of therapy 7-10 days, may not completely eliminate parasites 3) exchange transfusions in seriously ill patients

Related

Babesia microti gametocyte malaria schizogony trophozoite

General

protozoan infection

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2009, 2012, 2015, 2018, 2021. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 1264-65
  3. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, 1188
  4. Herwaldt BL et al. Transfusion-associated babesiosis in the United States: A description of cases. Ann Intern Med 2011 Sep 5 PMID: 21893613 - Leiby DA. Transfusion-associated babesiosis: Shouldn't we be ticked off? Ann Intern Med 2011 Sep 5 PMID: 21893616
  5. ARUP Consult: Babesia microti - Babesiosis The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/babesia-microti
  6. 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 Nov 1;43(9):1089-134 PMID: 17029130 corresponding NGC guideline withdrawn Feb 2016
  7. Blevins SM, Greenfield RA, Bronze MS Blood smear analysis in babesiosis, ehrlichiosis, relapsing fever, malaria, and Chagas disease. Cleve Clin J Med. 2008 Jul;75(7):521-30 PMID: 18646588
  8. Vannier E, Krause PJ. Human babesiosis. N Engl J Med. 2012 Jun 21;366(25):2397-407. PMID: 22716978
  9. DermNet NZ. Babesiosis http://www.dermnetnz.org/arthropods/babesiosis.html
  10. Cunha BA, Bronze MS (images) Medscape: Baesiosis http://emedicine.medscape.com/article/212605-overview
  11. Wikipedia: Babesiosis (image) https://en.wikipedia.org/wiki/Babesiosis
  12. Centers for Disease Control & Prevention (CDC) Babesiosis (Babesia spp.) 2011 Case Definition. https://wwwn.cdc.gov/nndss/conditions/babesiosis/case-definition/2011/
  13. Manian FA, Barshak MB, Lowry KP, Basnet KM, Stowell CP. CASE RECORDS of the MASSACHUSETTS GENERAL HOSPITAL. Case 27-2016. N Engl J Med. 2016 Sep 8;375(10):981-91. PMID: 27602671
  14. Akel T, Mobarakai N. Hematologic manifestations of babesiosis. Ann Clin Microbiol Antimicrob. 2017 Feb 15;16(1):6. Review. PMID: 28202022 Free PMC Article
  15. Westblade LF, Simon MS, Mathison BA, Kirkman LA. Babesia microti: from Mice to Ticks to an Increasing Number of Highly Susceptible Humans. J Clin Microbiol. 2017 Oct;55(10):2903-2912. PMID: 28747374 Free PMC article. Review.