Avian Chlamydiosis / Psittacosis / Ornithosis (Chlamydia psittaci)
Scientific manual covering Chlamydia psittaci elementary bodies, fibrinous polyserositis, zoonotic risk, and Doxycycline therapy.
Scientific Overview
Avian Chlamydiosis (Psittacosis in parrots, Ornithosis in poultry/turkeys) is a major systemic bacterial disease and regulated zoonosis caused by Chlamydia psittaci. In turkeys, ducks, and chickens, it causes fibrinous polyserositis, airsacculitis, hepatomegaly, respiratory distress, and severe public health risks to farm workers.
Etiology, Biphasic Life Cycle & Zoonosis
Chlamydia psittaci is defined as an obligate intracellular Gram-negative bacterium exhibiting a unique biphasic developmental cycle alternating between infectious Elementary Bodies (EBs) and metabolically active Reticulate Bodies (RBs).
Zoonotic Risk: C. psittaci is readily transmitted to humans via aerosolized fecal dust, causing severe atypical pneumonia, fever, and endocarditis in farm workers and slaughterhouse personnel.
Necropsy Lesions & Clinical Signs
Clinical necropsy findings in affected turkeys and ducks:
- Fibrinous Polyserositis: Thick yellow fibrin coats the heart (pericarditis), liver (perihepatitis), and air sacs.
- Hepatomegaly & Splenomegaly: Liver and spleen are markedly enlarged, congested, and dark black-purple with focal necrosis.
- Yellow-Green Diarrhea: Gelatinous green droppings accompanied by conjunctivitis and rhinitis.
Veterinary Doxycycline Protocol & Quarantines
Chlamydia lacks peptidoglycan synthesis pathways, rendering penicillins ineffective. Treatment requires prolonged oral Doxycycline or Chlortetracycline (400 mg/kg feed for 30–45 days) under strict quarantine and N95 respiratory protection for handlers.