Chlamydiosis (Avian)

Agricultural Disaster Preparedness and Recovery November 04, 2011 Print Friendly and PDF

Avian chlamydiosis is an infectious disease of psittacine birds (parrots), pigeons, doves, turkeys, and ducks caused by the Chlamydophila psittaci bacteria. Birds infected with the disease shed large amounts of the bacteria in their feces. Other birds contract the disease by inhaling dust or ingesting food contaminated with the bacteria.

Humans can become infected by C. psittaci by inhaling dust that is contaminated with feces or feathers or by handling infected birds directly. In people, this disease is called Psittacosis.


Endemic Areas

C. psittaci bacteria are found worldwide but are especially prevalent in psittacine birds of tropical and subtropical areas.


Clinical Signs

  • Ruffled feathers
  • Yellowish-green watery diarrhea
  • Nasal beak) discharge
  • Depression
  • Weakness
  • Weight loss due to decreased appetite
  • Conjunctivitis (pinkeye)
  • Difficulty breathing



Antibiotics may be used to treat avian chlamydiosis. Any bird suspected of having avian chlamydiosis should be reported to the State Veterinarians or USDA Area Veterinarian in Charge immediately.



Avian chlamydiosis infection may be prevented by following USDA-APHIS Biosecurity for the Birds recommendations. These include isolating sick birds, preventing contact with wild birds, and quarantining birds of unknown health status entering a flock.


Public Health

Contact with C. psittaci-infected birds and inhaling dust contaminated with feces or feathers are the main modes of psittacosis transmission. Symptoms include fever, chills, headache, weakness, difficulty breathing, dry cough, and sore throat. In rare cases, psittacosis may result in severe systemic infections including encephalitis (inflammation of the brain), myocarditis (inflammation of the heart muscle), and hepatitis (inflammation of the liver). In most cases, people recover with appropriate antibiotic treatment.



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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.