Psittacosis (Parrot Fever) in Birds

Causes, Treatment, and Prevention

Macaw parrot

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Also known as parrot fever or avian chlamydiosis, psittacosis is an avian disease that many bird owners will encounter when caring for their pets. Psittacosis can be severe and even life-threatening, causing symptoms like lethargy, loss of appetite, weight loss, and more. This zoonotic disease can be found in many different species of birds, including popular pets like macaws, parakeets, cockatiels, Amazon parrots, cockatoos, lories, African grey parrots, lovebirds, conures, pigeons, and even pet ducks. Psittacosis is contagious and can spread through the air, and it can even infect humans. Bird owners should learn about the signs and prevention methods associated with psittacosis to help minimize the risk of this disease affecting their homes.

What Is Psittacosis?

Psittacosis is an infectious disease caused by the bacterium Chlamydophila psittaci, affecting more than 400 species of birds and some mammals. It may also be caused by Chlamydophila avium, Chlamydophila gallinacea, and other bacteria. Psittacosis is transmitted from bird to bird, but it can also be contagious to some mammals (including humans) through infected birds. C. psittaci is the bacterium that is typically seen in pet psittacines like parrots and is most commonly diagnosed.

Symptoms of Psittacosis in Birds

In birds, psittacosis causes a variety of symptoms, but it can also go unnoticed and lay dormant without signs. Birds that are acutely infected from exposure to the bacterium (which come in contact with an infected bird or item) will show symptoms after about three days, while carriers of the bacterium can become sick at any time. Infected birds are asymptomatic until they become stressed. This triggers the onset of symptoms, and bird owners may observe the following:


  • Puffy and swollen eyes
  • Lethargy
  • Loss of appetite and weight loss
  • Fluffed feathers
  • Nasal discharge
  • Abnormal droppings

Puffy and Swollen Eyes

Also known as conjunctivitis, puffy and swollen eyes is a common symptom in birds with psittacosis. This is due to inflammation that affects the blood vessels in and around the eye.


Lethargy is a symptom of many diseases that affect birds, humans, and other species. Various feelings of illness that your bird may endure throughout a case of psittacosis can cause its energy levels to lower, limiting normal behaviors like playing, vocalizing, and flying.

Loss of Appetite and Weight Loss

If you notice that your bird is not eating normal amounts of food, weight loss may follow. Talk to your exotic veterinarian about helping your bird maintain a healthy weight and consume vital nutrients when it's not feeling well.

Fluffed Feathers

Your bird may fluff its feathers to stay warm. Psittacosis commonly causes birds to feel cold and shiver, so fluffed feathers can be an indicator of this disease (although birds also fluff their feathers to demonstrate emotions like excitement, anxiety, anger, or happiness).

Nasal Discharge

Discharge from your bird's nasal cavity is common during cases of psittacosis. This may happen alongside respiratory issues like labored breathing.

Abnormal Droppings

Your bird's droppings can become runny, discolored, or otherwise abnormal for a variety of reasons. However, in combination with other symptoms of psittacosis, this may mean that its liver has been infected by the bacteria. Owners may notice discoloration of yellow or green varieties.

Causes of Psittacosis

Psittacosis is a highly contagious disease. Because it is able to spread through inhalation, it's common for psittacosis to infect more than one member of the same household (including birds, humans, and other animals). The following causes may occur:

  • Contact with infected birds: A fast way for birds to contract psittacosis is through contact with an infected bird, breathing in the same area, and ultimately spreading the infection.
  • Contaminated items: Psittacosis can spread when birds come in contact with items like food, water bowls, dropped feathers, and other items that have been contaminated by another bird (even if the other bird is not present).
  • Airborne infection: Being in the same room with poor ventilation as an infected bird can also cause your pet bird to contract the disease. This is also a way for psittacosis to spread to humans caring for infected birds.

The most commonly infected species of pet birds are those in the psittacine family (often referred to as parrots). These include macaws, budgerigars (parakeets), cockatiels, Amazon parrots, cockatoos, lorikeets, African grey parrots, lovebirds, and conures. Pet pigeons are also often infected with psittacosis, as are pet ducks. Hundreds of other species of birds are also susceptible to this disease, including wild birds.

Diagnosing Psittacosis in Birds

Since psittacosis symptoms can look like an array of other diseases in pet birds, special tests are needed to diagnose the presence of C. psittaci. In most cases, a blood test is best, as this can tell your veterinarian if the bird is infected even without the presence of symptoms. Histology (looking at tissues under the microscope), the detection of nucleic acids and antigens, various serological tests, and cultures may also be recommended by an avian vet to diagnose your bird with psittacosis. Sometimes more than one test is needed.

The bacterium can be detected in a number of bodily areas including the feces, liver, lungs, kidneys, spleen, excretions from the eyes, the choana, cloaca, and even the tissue that covers the heart called the pericardium. Birds that are experiencing symptoms of psittacosis are easier to diagnose than birds that are not showing any signs of the disease. Sometimes multiple fecal samples must be tested in order to find the bacterium, although fecal tests are not effective for diagnosis unless the bird is actively shedding the organism.


Thankfully, there is a treatment for psittacosis. Since birds cannot safely take the same kinds of antibiotics as other animals, your bird's veterinarian will likely prescribe doxycycline, an antibiotic in the tetracycline class of drugs, for 45 days to treat the disease through all stages. If your bird does not have C. psittaci, another type of antibiotic in the sulfonamide class may be successful as well, but this drug class does not have any effect on the most commonly diagnosed type of bacterium to cause psittacosis.

Prognosis for Birds With Psittacosis

About 50 percent of birds are said to die from psittacosis infections if left untreated, but antibiotics are usually successful in treating it. If your bird is presenting any of the symptoms associated with this disease, schedule an avian veterinary exam as soon as possible to begin treatment. Follow-up exams may be recommended to ensure the infection is cleared after 45 days of medication.

How to Prevent Psittacosis

Like other avian diseases, it's best for bird owners to try preventing infections of psittacosis before they occur. Proper sanitary practices, quarantine procedures, and the isolation of infected birds are essential:

Cleanliness During Handling

Certain disinfectants can kill the bacteria that causes psittacosis, so cleanliness is important in preventing this disease. If you attend a bird show or visit the pet store, make sure you wash your hands thoroughly between handling birds and before handling your own bird. Even items for sale at a pet store or bird show (such as food dishes, cages, and toys) can harbor fomites from infected birds and should be washed before being brought home to your bird.

Sanitation Involving Wild Birds

Wild birds can also carry psittacosis. Baby birds that fall out of the nest, dead birds, and injured birds are all commonly handled by humans and can carry psittacosis. If you handle wild birds (especially seabirds), be sure to wash your hands prior to handling your pet bird.

Quarantining New Birds

If you plan on adopting or purchasing a new pet bird, be sure to quarantine the bird prior to introducing them to another. This will allow time for you to monitor them for any signs of psittacosis. Be sure to practice good hygiene during this quarantine period or wear disposable gloves and a mask, especially if the source of the bird does not provide its medical history.

Isolating Infected Birds

If you have multiple birds and one is diagnosed with psittacosis, isolate that bird from the others immediately to minimize the risk of spreading the infection. Good ventilation, clean environments, and hand washing are all crucial to preventing the transmission of psittacosis at home.

Is Psittacosis Contagious to Humans?

Psittacosis is contagious to humans, and handling an infected bird can cause its owners to develop this disease. It can spread through inhalation, so being in close conditions with your bird is a risk. Try to increase ventilation in the room where your bird is kept by opening the windows and turning on fans. Always wear a mask and gloves when feeding or handling a diseased bird, and sanitize your home frequently.

The symptoms of psittacosis in humans and other mammals are different than those of birds. In humans, psittacosis typically causes respiratory disease, fever, chills, fatigue, muscle pain, dry cough, and more. In some mammals like cows and pigs, psittacosis can cause miscarriage and reproductive problems along with eye issues, lameness, fever, and nasal discharge.

Psittacosis can be fatal in untreated animals that show symptoms, but many are asymptomatic. A variety of the symptoms can also indicate other kinds of diseases, so it is hard to diagnose psittacosis by looking at symptoms alone. Always tell your doctor about any possible exposures to infected animals to help them determine whether psittacosis is the cause of your symptoms.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Bacterial Diseases of Pet Birds. Merck Veterinary Manual.

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  4.  Overview of Chlamydiosis. Merck Veterinary Manual.

  5. How to Prevent Psittacosis. Centers for Disease Control and Prevention.