Avian chlamydiosis is a bacterial disease caused by Chlamydia psittaci, which is carried commonly by birds. Humans can catch the disease by breathing in dust containing dried saliva, feathers, mucous and droppings from infected birds. Infection in humans is called psittacosis.

Last updated: 12 March 2024

What is avian chlamydiosis?

Avian chlamydiosis (AC) is a disease of birds caused by the bacteria Chlamydia psittaci. AC is common in wild, caged and aviary birds. All birds can be infected by AC, but pet birds, especially parrots (e.g. budgies, lorikeets and cockatiels) most commonly pass infection to humans. Infection in humans causes psittacosis, which is frequently a mild flu-like illness that can sometimes result in a severe pneumonia.

How is it spread?

Spread between birds (and to people) occurs mainly through breathing in dust containing dried saliva, feathers, mucous and droppings from infected birds. Direct contact with feathers, bird droppings and litter, saliva and mucous, and contaminated food or water can also result in disease. The organism is resistant to drying and can remain infectious for several months if protected by organic debris (e.g. litter or faeces).

What are the signs of AC in birds?

The signs of AC vary depending on the species of bird and the strain of C. psittaci involved. Birds with an AC infection may not look sick and so can carry the disease for long periods. If they are sick (usually young birds), the signs can include:
  • mucous or pus coming from the nostrils and eyes
  • cough
  • diarrhoea or dark green droppings
  • poor feeding
  • difficulty moving or flying
  • death, which can sometimes be sudden with no warning signs.
Stress (e.g., from transport, or a new environment) may cause the appearance of clinical signs in birds that otherwise carry the organism without symptoms.

How is AC diagnosed and treated?

Several tests are available to confirm AC infection. These need to be discussed with your veterinarian. Testing can be done either when the bird is alive or when it is recently deceased. Infected birds need to be isolated, receive a long course of antibiotics and have their cages disinfected. Treatment is not always 100% effective at clearing the infection so AC can return after treatment is finished and the same bird can be re-infected with a different strain of C. psittaci. Treatment and control measures should be supervised by a veterinarian.

How can I prevent transmission and infection?

Educate persons at risk

  • All people in contact with birds or bird-contaminated materials should be aware of the potential health risks.
  • Bird caretakers with respiratory or influenza-like symptoms should seek prompt medical attention and inform their health care provider about bird contact.

Be alert for symptoms

  • Avoid purchasing or selling birds that have any clinical signs or appear unwell.
  • Maintain accurate records of all bird-related transactions for at least one year to aid in identifying sources of infected birds and potentially exposed persons.
  • Where possible, quarantine newly acquired birds for 30 days or test/treat them before adding to a group. Birds that have been to shows, exhibitions, fairs and other events should also be quarantined.

Practice preventive husbandry

  • Position cages so droppings, feathers, food, and other materials can’t spread from one cage to another.
  • Do not stack cages and use solid-sided cages or barriers if cages are adjoining.
  • Ensure adequate ventilation and light in the room.
  • Use litter that will not produce dust (e.g. newspaper).
  • Clean all cages, food bowls, and water bowls daily.
  • Use a disinfectant solution when cleaning. All surfaces should be thoroughly cleaned of organic debris (e.g. litter or faeces) before disinfection. Appropriate disinfectants are quaternary ammonium compounds such as benzalkonium chloride, 3% hydrogen peroxide, alcoholic iodine solutions or 70% ethanol. Hospital grade disinfectants based on sodium hypochlorite are also suitable. A 1:100 dilution (10mL/L) should be prepared immediately before use, and discarded at the end of each disinfection session.
  • Empty soiled bowls, clean with soap and water, rinse, disinfect, and rinse again before reuse.
  • Scrub cages with soap and water, disinfect and rinse in clean running water between use by different birds.
  • Isolate sick birds and disinfect their cages under veterinary supervision. Recommend not to sell sick birds due to human health risk.

Protect yourself

  • Wash your hands with soap and running water for 10 seconds before and after handling birds.
  •  When cleaning cages or handling potentially infected birds, caretakers should wear appropriate protection to reduce exposure to dust without appropriate protection. 
  • Avoid very close contact with potentially infected birds or take appropriate measures to reduce the risk, such as gloves, protective eyewear, and a properly fitted P2 respirator (available from most pharmacies and hardware stores). Surgical masks are not effective in preventing transmission. See How to fit a P2 mask.
  • Wetting the litter before cleaning reduces the risk of disease.
  • Always use disinfectants in a well-ventilated area as they can irritate the nasal passages and lungs of both humans and bird.
Current as at: Tuesday 12 March 2024
Contact page owner: One Health