Giardiasis

Last reviewed: 24 Aug 2023
Last updated: 29 Dec 2022

Summary

Definition

History and exam

Key diagnostic factors

  • diarrhea
  • frequent belching
More key diagnostic factors

Other diagnostic factors

  • abdominal bloating and discomfort
  • malaise
  • weight loss
  • nausea and vomiting
Other diagnostic factors

Risk factors

  • contaminated water/food
  • domestic animals living in or around the house
  • hypogammaglobulinemia
  • young age
  • male sex
  • day-care center attendance
  • men having sex with men
  • recent antibiotic use
More risk factors

Diagnostic investigations

1st investigations to order

  • direct fluorescence antibody (DFA) test or enzyme-linked immunosorbent assay
  • nucleic acid amplification test, polymerase chain reaction of stool sample
  • stool microscopy
  • CBC
More 1st investigations to order

Investigations to consider

  • Lateral flow immunoassay (e.g., ImmunoCard STAT!)
  • string test (EnteroTest)
  • duodenal aspirates and biopsies
More investigations to consider

Treatment algorithm

ACUTE

nonpregnant adult or child

pregnant; first trimester

pregnant; second or third trimester

ONGOING

treatment failure or resistance

Contributors

Authors

Luther A. Bartelt, MD

Assistant Professor of Medicine

University of North Carolina School of Medicine

Division of Infectious Diseases

Chapel Hill

NC

Disclosures

LAB has received funding support from the National Institutes of Health to support giardiasis research and royalties from text authorships (Wolters Kluwer) for chapters about Giardia. LAB is the author of two articles cited in this topic.

Acknowledgements

Dr Luther Bartelt would like to gratefully acknowledge Dr Fida Khan and Dr Musaddiq Waheed, previous contributors to this topic.

Disclosures

FK and MW declared that they had no competing interests.

Peer reviewers

Zana Nikolla, MD

Faculty of Medicine

University of Tirana

Tirana

Albania

Disclosures

ZN declares that she has no competing interests.

Rodney Adam, MD

Professor of Medicine and Immunobiology

University of Arizona

Tucson

AZ

Disclosures

RA declares that he has no competing interests.

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  • Guidelines

    • Adverse events associated with EGD and EGD-related techniques
    • CDC yellow book: chapter 4 - travel-related infectious diseases: giardiasis
    More Guidelines
  • Patient leaflets

    Diarrhea in adults

    More Patient leaflets
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