Parrot Fever (Psittacosis) - Causes, Symptoms and Treatment

Macaw parrot
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There are a few diseases that frighten people more than others when their name is spoken and psittacosis is, unfortunately, one of them. Also known as parrot fever or avian chlamydiosis, psittacosis is a zoonotic disease that can be found in many different kinds of pet birds, including macaws and parakeets, and is easily spread.

What Is Psittacosis?

Psittacosis is a disease that affects over 400 species of birds and some mammals. It is caused by the bacterium Chlamydophila psittaci, Chlamydophila avium, or Chlamydophila gallinacea (but other bacterium are thought to also cause this disease) and is transmitted from bird to bird or bird to some mammals (including humans) by infected birds. C. psittaci is the bacterium that is typically seen in pet psittacines like parrots and is most commonly diagnosed.

How Do Birds Get Psittacosis?

A bird does not have to have contact with another bird that has been infected with one of the types of bacterium that causes psittacosis in order to get it, but this is an easy way for them to get it. They can also come in contact with a person or item that has been in contact with an infected bird. Fomites on food and water bowls, airborne particles, feathers, feces, and other items that have been in contact with a bird with psittacosis can all infect healthy birds. Being in the same room with poor ventilation as an infected bird can also cause your pet bird to get it.

What Are the Symptoms of Psittacosis in Birds?

In birds, psittacosis causes a variety of symptoms but it can also go unnoticed and lay dormant inside a bird. Psittacosis infected birds are asymptomatic (show no symptoms) until they are stressed and then it causes puffy and swollen eyes (conjunctivitis), lethargy, anorexia, and weight loss, fluffed feathers, nasal discharge, and an enlarged liver. It can also cause diarrhea and respiratory issues in some species of birds. Birds that are acutely infected from exposure to the bacterium (come in contact with an infected bird or item) will show symptoms after about three days. Carriers of the bacterium can become sick at any time.

What Are the Symptoms of Psittacosis in Mammals?

In mammals, psittacosis typically causes reproductive problems such as miscarriages and inflamed placentas and respiratory problems such as pneumonia, coughing, and an increased respiratory rate. It has also been reported to cause similar eye issues as it does in birds, 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.

How Can You Diagnose Psittacosis in Your Bird?

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. Histology (looking at tissues under the microscope), the detection of nucleic acids and antigens, various serological tests, and cultures may 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 places in your bird 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, especially in birds that are just carriers and not acutely ill.

What Bird Species Are Commonly Infected With Psittacosis?

The most commonly infected kinds of pet birds are those in the psittacine family (often referred to as parrots). These include macaws, budgerigars (parakeets), cockatiels, Amazon parrots, cockatoos, lories, African greys, 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.

Is There a Treatment for Psittacosis?

Thankfully there is a treatment for psittacosis. About 50% of birds are said to die from this infection if left untreated but antibiotics are usually successful in treating it. Since birds cannot safely take all the same kinds of antibiotics as other animals, they are typically prescribed doxycycline, an antibiotic in the tetracycline class of drugs, for 45 days to treat the disease. 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.

How Can You Prevent Psittacosis in Your Bird?

Certain kinds of disinfectants can kill the kinds of bacteria that cause psittacosis so cleanliness is important in preventing this disease. If you attend a bird show make sure you wash your hands thoroughly between handling birds and before handling your own bird. Even items for sale at the bird show, like food dishes, cages, and toys, can harbor fomites from infected birds and should be washed before brought home to your bird.

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

If you plan on adopting or purchasing a new pet bird, be sure to quarantine the bird prior to introducing them to another pet bird. 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 is skeptical. 

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