Parrot psittacosis — caused by the intracellular bacterium Chlamydia psittaci — is a serious respiratory and systemic infection that affects virtually all parrot species and can spread to humans, where it causes a flu-like or pneumonia-type illness. In birds, it ranges from asymptomatic shedding to fatal multi-organ disease. It is a reportable disease in the United States.
Last reviewed: June 2026
What Is Psittacosis in Parrots?
Psittacosis (also called chlamydiosis or ornithosis) is caused by Chlamydia psittaci, an obligate intracellular pathogen. In birds, infection may be latent (the bird is infected but not visibly ill), subclinical (mild, easily missed signs), or acute (severe multi-organ disease). Any stressor — shipping, new environments, overcrowding, concurrent infection, or breeding — can convert a latent infection into active disease with shedding.
C. psittaci is shed in respiratory secretions, feces, ocular discharges, and feather dust. It is hardy in the environment and can survive in dried fecal material for months. All parrot species can be affected — parakeets, cockatiels, African greys, Amazon parrots, macaws, and conures are commonly implicated. Per the AAV Basic Care for Companion Birds, 2019 and as described in Carpenter's Exotic Animal Formulary, routine screening with a C. psittaci PCR test is recommended for newly acquired birds before introduction to an existing collection.
Zoonotic risk: C. psittaci can infect humans via inhalation of contaminated dust or respiratory droplets. Human psittacosis typically presents as flu-like illness, atypical pneumonia, or severe systemic disease — with mortality if untreated and antibiotic therapy is delayed. Elderly, immunocompromised, and pregnant individuals are at highest risk. Psittacosis is a notifiable disease — US veterinarians are required to report confirmed cases to public health authorities.
Signs of Psittacosis in Parrots
Clinical signs vary from none to severe:
Respiratory signs:
- Discharge from nostrils (rhinitis)
- Sneezing
- Labored breathing, tail bobbing, or open-mouth breathing in severe cases
Eye signs:
- Conjunctivitis — red, swollen, or discharging eyes
- Epiphora (excessive tearing)
Systemic signs:
- Fluffed feathers, lethargy, weight loss
- Lime-green or yellow-green diarrhea — a classic though not specific finding; bile pigment is increased with liver involvement
- Enlarged liver or spleen (hepatosplenomegaly) on physical exam
Subclinical carriers shed the organism without obvious signs — this is why all new birds should be tested.
Diagnosis and Treatment
Diagnosis: C. psittaci PCR on choanal/cloacal swabs is the most sensitive test and is preferred over serology. Cytology or antigen testing can provide rapid in-clinic results. Bloodwork often shows elevated bile acids, heterophilia, and monocytosis.
Treatment: Doxycycline is the antibiotic of choice. As described in Plumb's Veterinary Drug Handbook, treatment in companion birds is typically 45 days of doxycycline (oral or injectable). Compliance is essential — incomplete courses lead to relapse and continued shedding. During treatment, avoid calcium-containing foods (dairy, cuttlebone, mineral blocks) which reduce doxycycline absorption.
Injectable doxycycline (Vibramycin) administered by a veterinarian every 5–7 days offers excellent compliance. Oral liquid doxycycline daily at home works but requires reliable owner administration. Formulated in-feed medicated feeds are available for aviaries managing multiple birds.
Affected birds should be isolated, and their cages, water bowls, and perches disinfected with 1:32 bleach solution. Owners should wear masks and gloves when cleaning during the treatment period, and household members with respiratory illness should consult a physician.
When to See a Vet
Call your vet today if:
- Your parrot has nasal discharge, sneezing, or eye discharge
- Your bird has lime-green droppings or is losing weight
- Any new bird has not been tested for C. psittaci
Go to the ER immediately if:
- Your parrot is at the bottom of the cage, barely moving, or breathing with visible effort
- Multiple birds in a collection are becoming ill simultaneously
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Frequently Asked Questions
Can I get psittacosis from my parrot? Yes — C. psittaci is a genuine zoonosis. Human infection occurs through inhalation of dried fecal dust or respiratory secretions. Most human cases present as a flu-like illness that responds to doxycycline treatment. Untreated human psittacosis can progress to severe pneumonia. Immunocompromised household members and pregnant women should avoid contact with a bird undergoing treatment.
Can a parrot with psittacosis look completely healthy? Yes. Subclinical and latent infections are common, and birds may shed infective C. psittaci for months without any visible signs. This is why PCR testing of all new birds before introduction to existing collections is strongly recommended by avian veterinarians.
How long does psittacosis treatment take in parrots? A 45-day course of doxycycline is the standard. Retesting by PCR 4 weeks after treatment completion confirms clearance. Some birds require longer courses if initial infection was severe or treatment compliance was imperfect.
How much does psittacosis testing and treatment cost? Avian exam runs $80–150. C. psittaci PCR testing adds $60–100 per bird. Injectable doxycycline appointments every 5–7 days (for 7–9 visits) cost $50–120 per visit at most avian practices. Oral liquid doxycycline for 45 days runs $40–80 total. Budget $400–800 for full diagnosis and treatment of a single bird.
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