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
| Method | Advantages | Disadvantages |
|---|---|---|
| Culture |
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| Serology (e.g., complement fixation, microimmunofluorescent antibody test) |
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| Nucleic acid amplification techniques (e.g., real-time PCR)1 |
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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.
- Balsamo G, Maxted AM, Midla JW, et al. Compendium of measures to control Chlamydia psittaci infection among humans (psittacosis) and pet birds (avian chlamydosis), 2017. J Avian Med Surg. 2017;31(3):262–82.
- Chlamydophila psittaci: Pathogen safety data sheet — infectious substances, Public Health Agency of Canada, April 2013.
- McGovern OL, Kobayashi M, Shaw KA, et al. Use of real-time PCR for Chlamydia psittaci detection in human specimens during an outbreak of psittacosis — Georgia and Virginia, 2018. MMWR Morb Mortal Wkly Rep. 2021:70(14):505–9.
- Mitchell SL, Wolff BJ, Thacker WL, et al. Genotyping of Chlamydophila psittaci by real-time PCR and high-resolution melt analysis. J Clin Microbiol. 2009;47(1):175–81.
- Wolff BJ, Morrison SS, Pesti D, et al. Chlamydia psittaci comparative genomics reveals intraspecies variations in the putative outer membrane and type III secretion system genes. Microbiology. 2015;161(7):1378–91.
Case report forms and other resources are available from the National Association of State Public Health Veterinarians.