Diagnosis, Treatment, and Prevention

Diagnosis of psittacosis can be difficult. Laboratories use several methods to detect Chlamydia psittaci infection. See the table below for advantages and disadvantages of different methods for diagnosing psittacosis.

Some tests are only available in specialized laboratories, and many laboratories may not offer any test for C. psittaci.  When additional or specialized testing is necessary, local or state public health laboratories may be able to provide diagnostic support or forward specimens 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 laboratory receiving the specimen.

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 a several weeks)
  • Technically difficult; requires specialized expertise
  • Must be cultivated within a tissue culture, mice, or chick embryo
  • Few laboratories perform
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
Molecular (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

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 outweighs 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.

References

Resources

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: August 22, 2019