Chlamydophilosis in Birds

By Rick Axelson, DVM

General Information

Chlamydophilosis, also called "psittacosis", "chlamydiosis" or "Parrot Fever", is a reasonably common disease of birds. It can occur in any bird but is especially common in cockatiels, Amazon parrots and budgerigars (often referred to incorrectly as parakeets.) The disease can cause chronic infections, asymptomatic infections or sudden death. The disease can also be transmitted to people. It is not associated with the venereal form of Chlamydophila that affects people.

What causes chlamydophilosis?

Chlamydophilosis is caused by an organism called Chlamydophila psittaci (or C. psittaci). This organism was recently renamed, and used to be called Chlamydia psittaci. This organism shares similarities with viruses and bacteria, but is different enough to be classified within its own special group. Like a virus, but unlike many bacteria, it lives right inside the cells of the bird, which makes it difficult to kill with treatment.

What are some common signs of chlamydophilosis in birds?chlamydophilosis-1

Chlamydophilosis can cause many different clinical signs, and therefore should be suspected in any sick bird. In general, birds with chlamydophilosis exhibit a decreased appetite, weight loss, lethargy, wet droppings, nasal discharges, shivering and breathing difficulties. C. psittaci may affect some or all of a bird's organ systems, most commonly the liver, spleen, respiratory tract and digestive tract. Commonly, chlamydophilosis causes chronic respiratory (sneezing, runny eyes or nose) or gastrointestinal signs (change in droppings).

"Some birds can carry Chlamydophila psittaci asymptomatically."

Classically, chlamydophilosis causes lime green or yellow feces and urates (the normally solid white part of the droppings) due to Chlamydophila infection of the liver. However, this is not seen all the time, and other diseases can also cause these discolored droppings. Some birds can carry Chlamydophila psittaci asymptomatically, which means they carry the infection, spread it to other birds (and people), but are not sick themselves. This is a good reason for testing all birds for chlamydiosis.

How is chlamydophilosis diagnosed?

"In sick birds, faster results can be obtained by checking the feces."

Several tests are available for diagnosing chlamydophilosis. Blood tests can usually tell if your bird is infected, even if it is not sick. Sick birds can have their feces checked for the organism as well; however, this test will be negative if the bird is infected but is not actively shedding the organism at the time of the sample collection. As a rule, most healthy birds are checked by one of the available blood tests. In sick birds, faster results can be obtained by checking the feces. Finally, special tests can be performed on the liver, spleen, heart, and air sacs of birds that have died to check for a C. psittaci infection.

How is chlamydophilosis treated?

"After the 45-day treatment, the bird must be retested for C. psittaci to make sure the treatment was effective."

Treatment is usually with oral or injectable doxycycline antibiotic. Since the doxycycline only kills the Chlamydophila organisms when they are active and dividing, and the organisms may become dormant, or cease being active for a period of time, the drug must be used for a minimum of 45 days. Since doxycycline often predisposes birds to yeast infections, your bird should also take an anti-yeast drug called nystatin during the treatment. After the 45-day treatment, the bird must be retested for C. psittaci to make sure the treatment was effective.

Can chlamydophilosis affect humans?

Yes! C. psittaci can be passed from bird to bird as well as from bird to human, usually by inhaling or ingesting contaminated fecal matter or dust. In humans, it often causes respiratory disease with chills, fever, the sweats, possible headache, fatigue, muscle pain, inappetence, nausea, vomiting, diarrhea and a dry cough. It can be like a flu that does not go away. If you think you might have this problem, seek help from your own medical doctor and tell your doctor that you own a bird and chlamydophilosis is a possibility.

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