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Psittacosis

Evidence last reviewed: 16 May 2026
Topic last updated: 10 Jun 2026

Summary

Definition

History and exam

Key diagnostic factors

  • illness in other family members
Full details

Other diagnostic factors

  • fever
  • malaise
  • myalgia
  • headache
  • cough
  • sore throat
  • rales
  • tachypnea
  • pharyngitis
  • conjunctivitis
  • gastrointestinal symptoms
  • rash
  • hepatomegaly
  • confusion
  • tachycardia
  • splenomegaly
Full details

Risk factors

  • exposure to infected birds and mammals
  • exposure to infected person
  • young children
  • older adults
  • immunocompromised
Full details

Diagnostic tests

1st tests to order

  • white blood cell count with differential
  • liver function tests
  • polymerase chain reaction (PCR)
  • chest x-ray
Full details

Tests to consider

  • serology
  • culture
  • metagenomic next-generation sequencing (mNGS)
Full details

Treatment algorithm

ACUTE

children ≥8 years of age and nonpregnant adults

children <8 years and pregnant women

Contributors

Authors

Deborah Dean, MD, MPH
Deborah Dean

Director Children’s Global Health Initiative

Professor of Medicine and Pediatrics, Division of Infectious Diseases and Global Health

University of California at San Francisco School of Medicine

Member, UCSF Bixby Center for Global Reproductive Health

Member, UCSF Benioff Center for Microbiome Medicine (BCMM)

Affiliate Faculty, UCSF Institute for Global Health Sciences

Core Faculty, the UC Berkeley - UCSF Graduate Program in Bioengineering

Oakland

CA

Disclosures

DD declares that she has no competing interests.

Peer reviewers

Servaas Morre, PhD

Head of Laboratory of Immunogenetics

VU University Medical Center

Department of Pathology

Laboratory of Immunogenetics

Amsterdam

Netherlands

Disclosures

SM declares that he has no competing interests.

William A. Petri, Jr., MD, PhD, FACP

Chief and Professor of Medicine

Division of Infectious Diseases and International Health

University of Virginia Health System

Charlottesville

VA

Disclosures

WAP declares that he has no competing interests.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

National Association of State Public Health Veterinarians (NASPHV). Compendium of measures to control Chlamydia psittaci infection among humans (psittacosis) and pet birds (avian chlamydiosis). 2017 [internet publication].Full text

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

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