Public Health Agency of Canada
Symbol of the Government of Canada

Share this page




NAME: Chlamydophila psittaci

SYNONYM OR CROSS REFERENCE: Psittacosis, parrot fever and ornithosis, previously known as Chlamydia psittaci Footnote 1.

CHARACTERISTICS: C. psittaci, of the Chlamydiaceae family, is a nonmotile, gram-negative, obligate intracellular pathogen Footnote 2, Footnote 3. Chlamydiaceae have a unique and complex biphasic life cycle, where only one stage is infective Footnote 4. Briefly, they have an elementary body form which is adapted for extracellular survival, which is also the infective form Footnote 5, and a reticulate body form which is involved in intracellular growth and replication Footnote 2, Footnote 3, Footnote 6.


PATHOGENICITY/TOXICITY: Diseases caused by C. psittaci infections are known as psittacosis, also known as “parrot disease” or ornithosis because the infection can be acquired from birds. Illnesses in humans include respiratory symptoms ranging from cough to severe chronic pneumonia, although mild and asymptomatic cases have also been observed Footnote 2, Footnote 4. Symptoms generally include fever, chills, headache, myalgia, non-productive cough, difficulty breathing and gastrointestinal symptoms Footnote 2, Footnote 7. Disease can also be manifested through an influenza-like illness, with pain in the back and abdomen, high fever, and aching muscles Footnote 4. Infection can result in complications such as anaemia, liver dysfunction, and gastrointestinal symptoms such as vomiting, constipation, and diarrhea Footnote 4. The central nervous system can also be affected, resulting in disorientation, depression, or delirium that precedes meningitis and encephalitis. Illness generally lasts for 10 to 14 days; more severe cases may last from 3 to 7 weeks Footnote 1. With appropriate antibiotic treatment the mortality rate is 1% Footnote 1, however, disease in pregnant women may result in abortion (due to placentitis) or premature birth, and can be fatal in rare cases Footnote 4, Footnote 8.

An additional strain of C. psittaci exists in cats where it causes rhinitis, pneumonia, and conjunctivitis. Transmission to humans is rare Footnote 4.

EPIDEMIOLOGY: C. psittaci is distributed worldwide and human cases occur both sporadically and in outbreaks Footnote 1, Footnote 2, Footnote 6, Footnote 7. Immunocompromised patients and people who have contact with birds have the highest risk of contracting psittacosis, however children are rarely infected Footnote 4, Footnote 6, Footnote 7.

HOST RANGE: Humans, sheep, cattle, goats, cats and at least 465 species of birds Footnote 6, Footnote 7, Footnote 9. Birds from the order of Psittacidae (cockatoos, parrots and parakeets) and pigeons are especially affected Footnote 7, Footnote 9.


MODE OF TRANSMISSION: Inhalation of contaminated aerosols that carry fecal matter, as well as coming into direct contact with contaminated feces, nasal discharge, infected ewes, lambs, birds, and infected body fluids, can cause infection in humans Footnote 2, Footnote 4, Footnote 7.

INCUBATION PERIOD: Usually 5 to 14 days but can be up to 1 month Footnote 7.

COMMUNICABILITY: Person-to-person transmission is not a significant risk Footnote 6, Footnote 10.


RESERVOIR: Birds, particularly Psittacine birds and pigeons Footnote 1.

ZOONOSIS: Yes, disease can be transmitted from birds that carry the bacteria Footnote 1.



DRUG SUSCEPTIBILITY: Sensitive to tetracyclines, erythromycin, and macrolides Footnote 4, Footnote 7.

DRUG RESISTANCE: Resistance to spectinomycin and rifampin has been observed in certain mutant strains, and development of resistance against tetracyclines and macrolides is a growing concern Footnote 11.

SUSCEPTIBILITY TO DISINFECTANTS: Disinfectants such as 1:1 000 dilution of quaternary ammonium compounds, 70% isopropyl alcohol, 1% Lysol, 1:100 dilution of household bleach or chlorophenols are suitable for cleaning potentially infected areas Footnote 6, Footnote 10. C. psittaci is resistant to acid and alkali Footnote 6, Footnote 10.


SURVIVAL OUTSIDE HOST: C. psittaci elementary bodies can remain infectious in the environment for months Footnote 6. It has been reported to survive for 15 days on dry inanimate surfaces Footnote 12.


SURVEILLANCE: Monitor for symptoms. Microimmunofluorescence test or ELISA methods are commonly used for serodiagnosis of C. psittaciFootnote 10. Increasingly, PCR based testing is used to provide definitive confirmation of infection Footnote 4.

Note: All diagnostic methods are not necessarily available in all countries.

FIRST AID/TREATMENT: Treatment with doxycycline, or tetracycline hydrochloride is recommended to prevent relapse. Macrolide drugs, azithromycin or erythromycin, can be used to treat children or pregnant women Footnote 7.


PROPHYLAXIS: None are currently available for human use. Vaccination of sheep may reduce incidence of infection.


LABORATORY-ACQUIRED INFECTIONS: 116 laboratory acquired infections and 10 deaths were reported. The majority (85%) of infections and all fatalities occurred prior to 1955 Footnote 13.

SOURCES/SPECIMENS: Tissues, feces, nasal secretions, placental materials and fluids, and blood from birds; blood, sputum and tissues of infected humans Footnote 4, Footnote 14.

PRIMARY HAZARDS: Exposure to aerosols and droplets while working with infected birds and tissues Footnote 14.

SPECIAL HAZARDS: May have adverse effects on the fetus if contracted during pregnancy Footnote 15. Close contact with infected animals can result in transmission of disease.


RISK GROUP CLASSIFICATION: Risk group 3 Footnote 16.

CONTAINMENT REQUIREMENTS: Containment Level 3 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures. Patient diagnostics can be performed in a Containment Level 2 facility.

PROTECTIVE CLOTHING: Personnel entering the laboratory should remove street clothing and jewellery, and change into dedicated laboratory clothing and shoes, or don full coverage protective clothing (i.e., completely covering all street clothing). Additional protection may be worn over laboratory clothing when infectious materials are directly handled, such as solid-front gowns with tight fitting wrists, gloves, and respiratory protection. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 17.

OTHER PRECAUTIONS: All activities with infectious material should be conducted in a biological safety cabinet (BSC) or other appropriate primary containment device in combination with personal protective equipment. Centrifugation of infected materials must be carried out in closed containers placed in sealed safety cups, or in rotors that are loaded or unloaded in a biological safety cabinet. The use of needles, syringes, and other sharp objects should be strictly limited. Open wounds, cuts, scratches, and grazes should be covered with waterproof dressings. Additional precautions should be considered with work involving animals or large scale activities Footnote 17.


SPILLS: Allow aerosols to settle, and while wearing protective clothing, gently cover the spill with paper towels and apply appropriate disinfectant starting at the perimeter, working inwards towards the centre. Allow sufficient contact time before clean up, and then repeat Footnote 17.

DISPOSAL: Decontaminate before disposal by steam sterilization, incineration, or chemical disinfection Footnote 17.

STORAGE: In locked, leak-proof containers that are appropriately labelled and secured Footnote 17.


UPDATED: December 2011

PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright ©
Public Health Agency of Canada, 2011


Footnote 1
Krauss, H., Weber, A., Appel, M., Enders, B., Isenberg, H. D., Schiefer, H. G., Slenczka, W., von Graevenitz, A., & Zahner, H. (2003). Bacterial Zoonoses. Zoonoses: Infectious Diseases Transmissible from Animals to Humans. (3rd ed., pp. 173-252). Washington, DC.: ASM press.

Footnote 2
Essig, A. (2007). Chlamydia and Chlamydophia. In P. R. Murray (Ed.), Manual of Clinical Microbiology (9th ed., pp. 1021-1035). Washington D.C.: ASM Press.

Footnote 3
Furrows, S. J., & Ridgway, G. L. (2006). Chlamydia spp. In S. H. Gillespie, & P. M. Hawkey (Eds.), Principles and Practice of Clinical Bacteriology (2nd ed., pp. 317-328). West Sussex: John Wiley & Sons, Ltd.

Footnote 4
Shakespeare, M. (2002). Zoonoses Pharmaceutical Press.

Footnote 5
Corsaro, D., & Greub, G. (2006). Pathogenic potential of novel Chlamydiae and diagnostic approaches to infections due to these obligate intracellular bacteria. Clinical Microbiology Reviews, 19(2), 283-297. doi:10.1128/CMR.19.2.283-297.2006

Footnote 6
Wendel, K. A. (2005). Diseases Due to Other Category B Bacterial Pathogens II: Psittacosis, Q fever and Typhus. In M. S. Bronze, & R. A. Greenfield (Eds.), Biodefense: Principles and Pathogens (pp. 493-498). Norfolk: Horizon Bioscience.

Footnote 7
Beeckman, D. S. A., & Vanrompay, D. C. G. (2009). Zoonotic Chlamydophila psittaci infections from a clinical perspective. Clinical Microbiology and Infection, 15(1), 11-17.

Footnote 8
Mardh, P. A. (2005). Chlamydia. In S. P. Borriello, P. R. Murray & G. Funke (Eds.), Topley & Wilson's Microbiology & Microbial Infections (10th ed., pp. 2006-2025). Washington, DC, USA: Edward Arnold (Publishers) Ltd.

Footnote 9
Kaleta, E. F., & Taday, E. M. A. (2003). Avian host range of Chlamydophila spp. based on isolation, antigen detection and serology. Avian Pathology, 32(5), 435-462.

Footnote 10
Smith, K. A., Bradley, K. K., Stobierski, M. G., & Tengelsen, L. A. (2005). Compendium of measures to control Chlamydophila psittaci (formerly Chlamydia psittaci) infection among humans (psittacosis) and pet birds, 2005. Journal of the American Veterinary Medical Association, 226(4), 532-539.

Footnote 11
Binet, R., & Maurelli, A. T. (2005). Frequency of spontaneous mutations that confer antibiotic resistance in Chlamydia spp. Antimicrobial Agents and Chemotherapy, 49(7), 2865-2873. doi:10.1128/AAC.49.7.2865-2873.2005

Footnote 12
Kramer, A., Schwebke, I., & Kampf, G. (2006). How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infectious Diseases, 6

Footnote 13
Pike, R. M. (1976). Laboratory associated infections: summary and analysis of 3921 cases. Health Laboratory Science, 13(2), 105-114.

Footnote 14
US Department of Health and Human Services. (1999). Biosafety in Microbiological and Biomedical Laboratories. In J. Y. Richmond, & R. W. McKinney (Eds.), (4th ed., pp. 118). Washington, D.C.: U.S. Government Printing Office.

Footnote 15
Collins, C. H., & Kennedy, D. A. (1999). Risk assessment. Laboratory-acquired Infections: History, incidences, causes and preventions (4th ed., pp. 225-239). Oxford , UK.: Butterworth Heninemann.

Footnote 16
Human Pathogens and Toxins Act. S.C. 2009, c. 24. Government of Canada, Second Session, Fortieth Parliament, 57-58 Elizabeth II, 2009, (2009).

Footnote 17
Public Health Agency of Canada. (2004). In Best M., Graham M. L., Leitner R., Ouellette M. and Ugwu K. (Eds.), Laboratory Biosafety Guidelines (3rd ed.). Canada: Public Health Agency of Canada.