Diagnosis, Treatment, and Prevention

Diagnosis of psittacosis can be difficult. Laboratories use several methods to detect Chlamydia psittaci infection, including culture, serology, and nucleic acid amplification techniques. Rarely, C. psittaci has been detected by other methods, including metagenomic sequencing.

See the table below for advantages and disadvantages of different methods for diagnosing psittacosis. Refer to the psittacosis case definition for National Notifiable Disease Surveillance System laboratory criteria for diagnosis.

Some tests are only available in specialized laboratories, and many laboratories may not offer any test for C. psittaci. In addition, some laboratories may only test animal specimens. When additional or specialized testing is necessary, federal, state, or local public health laboratories may be able to provide diagnostic support or specimens may be forwarded to CDC.

Laboratories typically perform tests on sputum specimens or swabs of the nasopharynx and oropharynx or serum, depending on the method used. In severe cases, other specimen types may be used. Clinicians should confirm the recommended specimen types with the testing laboratory.

Advantages and disadvantages of select C. psittaci diagnostic methods

Advantages and disadvantages of select C. psittaci diagnostic methods
Method Advantages Disadvantages
Culture
  • Yields clinical isolate for genotyping, antimicrobial susceptibility testing, and next generation sequencing
  • Time-consuming (may take up to  several weeks)
  • Technically difficult; requires specialized expertise
  • Must be cultivated within a tissue culture, mouse, or chick embryo
  • Test not widely available in clinical laboratories
Serology (e.g., complement fixation, microimmunofluorescent antibody test)
  • Tests are available in many clinical laboratories
  • Cross-reactivity with other Chlamydia species may occur
  • Requires acute and convalescent samples, and delays confirmation
Nucleic acid amplification techniques (e.g., real-time PCR)1
  • Rapid detection
  • High sensitivity and specificity
  • Provides results in time for a treatment decision
  • Useful for strain typing
  • Requires specialized reagents and equipment
  • Test not widely available in clinical laboratories

Treatment

Chlamydia psittaci are sensitive to both macrolides and tetracyclines. However, tetracyclines are the drugs of choice, unless contraindicated due to reported macrolide failures. Tetracyclines are generally avoided in children aged <8 years, and macrolides are the drug of choice for children; however, tetracyclines could be considered when the benefits outweigh the risks, such as in life-threatening conditions or when macrolide failure is suspected.

As psittacosis can be difficult to diagnose, clinicians should be aware that proper antibiotic treatment ensures quick recovery time. People with more severe presentation should be treated with doxycycline right away if psittacosis is suspected.

Prevention

Patient isolation and prophylaxis of contacts are usually not indicated, as person-to-person transmission of C. psittaci is rare.

Most states require clinicians to report cases of psittacosis to the appropriate health authorities. Timely diagnosis and reporting may aid in identifying the source of the infection and controlling the spread of disease.

Educate patients about the importance of handling birds and cleaning bird cages safely. Refer birds suspected as the source of human infection to veterinarians for evaluation and treatment.

Case report forms and other resourcesexternal icon are available from the National Association of State Public Health Veterinarians.

1 The National Notifiable Diseases Surveillance System case definition currently considers an illness with characteristic symptoms and detection of C. psittaci nucleic acid in patient specimen via real-time polymerase chain reaction (PCR) to be a probable, but not confirmed, case.

Page last reviewed: March 17, 2022