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.
INFECTIOUS DOSE: Unknown.
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.
RESERVOIR: Birds, particularly Psittacine birds and pigeons Footnote 1.
ZOONOSIS: Yes, disease can be transmitted from birds that carry the bacteria Footnote 1.
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.
PHYSICAL INACTIVATION: Unknown.
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.
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.
Public Health Agency of Canada, 2011