Avian chlamydiosis is caused by Chlamydia psittaci, a bacterium that infects pet birds — including budgies, cockatiels, and parrots — and can spread to people, where it causes a flu-like illness called psittacosis. Per Balsamo et al., 2017, J Avian Med Surg, prompt diagnosis and treatment of infected birds protects both bird and human household members.
Last reviewed: May 2026
What It Looks Like in a Budgie
Infected budgies can be asymptomatic carriers for months — shedding bacteria in droppings, respiratory secretions, and feather dander without obvious illness. When symptoms appear, they include fluffed-up posture, lethargy, decreased appetite, yellow-green watery droppings (sometimes with urate changes), oculonasal discharge, swollen eyes, sinusitis, and respiratory difficulty (tail bobbing, open-mouth breathing). Severe cases progress to liver disease, neurologic signs, and death. The classic image of a "sick budgie" — fluffed, eyes half-closed, sitting on the cage bottom — is consistent with many diseases, including chlamydiosis.
Why It Matters to People
Psittacosis is a notifiable zoonotic disease in most US states. People typically develop a flu-like illness 5 to 14 days after exposure: fever, headache, dry cough, muscle aches, and chills. Severe cases can progress to pneumonia and require hospitalization. The 2017 Compendium recommends that any newly diagnosed bird trigger a discussion with household members about exposure and notification of their physician if symptoms develop. Risk is highest with new birds from pet stores, bird shows, or rescue settings; long-term solitary pets are lower risk if no new exposures occur.
How Vets Diagnose It
Diagnosis is challenging because the bacterium sheds intermittently and serology can lag clinical disease. Current testing typically combines PCR on a choanal swab, cloacal swab, and dropping sample with serology for antibody response. Bloodwork often shows elevated white cell counts, abnormal liver enzymes, and changes in plasma proteins. Per AAV Basic Care for Companion Birds, 2019, new bird quarantine of 30 to 45 days with testing is the most reliable way to detect chlamydiosis before introduction to an existing flock.
Treatment
Treatment is oral doxycycline for 45 days, the duration needed to clear intracellular bacteria. Compounded liquid doxycycline or doxycycline-medicated water (with veterinary guidance on concentration) are common. Supportive care during treatment includes warm housing, easy access to food and water, nutritional support if appetite is reduced, and rest. All birds in the household should be evaluated and often treated together, because cross-infection is common. After treatment, repeat PCR testing confirms clearance.
When to See a Vet
Call your vet today if:
- Fluffed-up posture or sitting on cage floor in a usually active bird
- Yellow, green, or watery droppings
- Eye or nasal discharge
- Reduced appetite or weight loss
- Recent introduction of a new bird with any signs in any bird in the household
Go to the ER immediately if:
- Severe labored breathing with mouth open or tail bobbing
- Sudden collapse or inability to perch
- Seizures or tremors
- Bleeding from the vent or mouth
- Profound weakness, especially with respiratory signs
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Frequently Asked Questions
How much does diagnosis and treatment cost?
Avian vet exam plus PCR panel (choanal, cloacal, and fecal) runs $200 to $500 per bird. Bloodwork adds $100 to $250. A 45-day course of doxycycline (compounded liquid) typically costs $80 to $200 per bird. Hospitalization for severely ill birds adds $300 to $1,200. Multi-bird households often need testing and treatment of all birds, increasing total cost.
Can my child or I catch psittacosis?
Yes — it is a documented zoonotic risk. Most exposed people do not become ill, especially with brief contact. Higher-risk exposures include cleaning cages without ventilation, kissing the bird, prolonged close contact with a heavily infected bird, and handling dead birds. Wash hands after bird contact, clean cages with proper ventilation, and inform your physician if you or a family member develops a flu-like illness within 2 weeks of bird exposure.
Should I quarantine new birds?
Yes — 30 to 45 days of strict quarantine in a separate room with separate air handling, dedicated cleaning supplies, and avian vet examination including chlamydia testing is the gold standard. Most outbreaks in established flocks come from inadequately quarantined new birds.
Will my bird recover fully?
Most birds treated with the full 45-day doxycycline course recover fully, especially if diagnosed early. Severely ill birds with significant liver damage have a more guarded prognosis. Repeat PCR after treatment confirms clearance — some birds need a second course.
Are some birds more prone?
Budgies, cockatiels, and lovebirds are commonly affected, but any psittacine bird can carry the organism. Recently weaned or stressed birds, large multi-bird collections, and breeder facilities have higher prevalence than long-term solitary pet birds.
Still Not Sure if Your Bird Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of your budgie's droppings (color and consistency), any eye or nasal discharge, and overall posture, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.