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Last reviewed: 16 Mar 2025
Last updated: 06 Jun 2023

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors

Other diagnostic factors

  • constitutional symptoms
  • pyrexia
  • jaundice
  • hepatosplenomegaly
  • petechiae, splinter haemorrhages, or ecchymoses
  • dark urine
  • conjunctival injection
  • cough
  • sore throat
  • photophobia

Risk factors

  • residence in or travel to an endemic region
  • exposure to Ixodes scapularis ticks
  • blood transfusion
  • asplenia
  • immunosuppression
  • age >50 years
  • Lyme disease
  • human granulocytic anaplasmosis
  • maternal infection during pregnancy

Diagnostic investigations

1st investigations to order

  • peripheral blood smear (Giemsa or Wright stained)
  • polymerase chain reaction for babesial DNA
  • FBC
  • serum creatinine and urea
  • LFTs
  • urinalysis
  • ELISA and/or immunofluorescence assay for Lyme disease
  • polymerase chain reaction and/or immunofluorescence assay or buffy coat smear for human granulocytic anaplasmosis

Investigations to consider

  • indirect immunofluorescence antibody assay for Babesia microti
  • IgG/IgM immunoblot for Lyme disease
  • HIV serology

Treatment algorithm

Contributors

Authors

Sarah Hochman, MD

Assistant Professor

Department of Medicine

Division of Infectious Diseases and Immunology

New York University School of Medicine

New York

NY

Disclosures

SH declares that she has no competing interests.

Louis Weiss, MD, MPH
Louis Weiss

Professor of Medicine

Division of Infectious Diseases

Professor of Pathology

Division of Parasitology and Tropical Medicine

Albert Einstein College of Medicine

Bronx

NY

Disclosures

LW has received grant funding from the National Institute of Allergy and Infectious Diseases. He is also the author of references cited in this topic.

Peer reviewers

Jeremy Gray, BSc, MSc, PhD

Professor

Department of Environmental Resource Management

University College Dublin

Belfield

Dublin

Republic of Ireland

Disclosures

JG declares that he has no competing interests.

Sam Telford III, ScD

Associate Professor of Biomedical Sciences

Division of Infectious Diseases

Cummings School of Veterinary Medicine

Tufts University

Boston

MA

Disclosures

ST has active research funding from the NIH. ST is an author or co-author of numerous primary publications on the biology of babesiosis, as well as reviews that have been referenced in this topic.

Raymond J. Dattwyler, MD

Professor of Medicine and Microbiology/Immunology

Chief of Allergy, Immunology and Rheumatology

New York Medical College

Valhalla

NY

Disclosures

RJD declares that he has no competing interests.

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