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Avian Chlamydiosis

Ornithosis, Psittacosis, Parrot Fever, Louisiana Pneumonitis, Chlamydophilosis

Avian chlamydiosis is a bacterial disease caused by the Chlamydia genus, which is well known for its high zoonotic potential for infection in huamns. The genus are widely distributed throughout the world, and known to contain 11 species, each having it's own specific range of hosts. Ducks are most commonly infected with C. ornithosis and C. psittaci. Ducks infected with C. psittaci most often develop enteric disease or act as subclinical carriers, displaying no signs of disease. Whether symptoms develop in ducks depends on the virulence of the chlamydial strain and immune status of the bird.

C. psittaci are most commonly spread to ducks through ingestion or inhalation of the organism from contaminated environments, feed, or water. Contamination occurs from carriers (infected or recovered birds that shed the organism within their feces, nasal or eye secretions). In some cases, ducks can get infected but display no clinical signs of being infected, however they will still shed C. psittaci in their feces. C. psittaci is very hardy and is able to survive in the environment, including airborne particles and dust, for several months. They can also be transmitted through respiratory secretions and fecal material of infected birds. Many birds are often asymptomatic carriers (meaning they are infected and regularly shed the bacteria in their feces, however show no clinical signs of infection.


Body tremors
Loss of appetite
Nasal discharge
Eye discharge
Weight loss
Yellow to greenish diarrhea
Ruffled feathers
Unthrifty appearance


  • History
  • Clinical signs
  • Fluorescent antibody
  • CI
  • Immunohistochemistry
  • ELISA - detection of antigens
  • Histopathology


MethodMethod Summary
Report diseaseAvian chlamydiosis is a reportable disease in the United States, meaning that if you suspect that your duck has this disease, by law you need to report it to your veterinarian, or a state or federal veterinarian.
Chlortetracycline1 g/L administered in drinking water, once daily
Doxycycline8-25 mg/kg oral twice daily, or 240 ppm in feed daily for 45 days
Enrofloxacin (Baytril)10 mg/kg administered intramuscularly twice daily for 14 days


  • Cover waterers, feeders, and swimming pool to prevent wild birds from contaminating with their feces
  • Good general hygiene
  • Quarantine any new birds


Risk Factors

  • High populations of wild birds
  • Introduction of a new flock member without quarantining first
  • Exposure to pet bird feces