Psittacosis (Parrot Fever)

posted: 05/15/12
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Psittacosis is also known as 'parrot fever,' ornithosis, or chlamydiosis. It is a widespread disease caused by an organism called Chlamydia psittaci. Psittacosis can infect a variety of species including humans, birds, cows, cats, goats, sheep, and pigs. Among the bird species, it will infect just about anything with feathers including psittacines, ratites, pigeons, poultry, ducks, and other migratory birds.

The transmission from bird to bird is primarily by inhalation of infected dust from droppings or feathers. It is often seen in birds that have been in close quarters such as quarantine stations, pet shops, or boarding facilities. Birds tend to shed the organism if stressed but may not show any signs of the disease.


No symptoms are specific to psittacosis. Birds can show any of the following signs: lack of appetite, weight loss, depression, listlessness, watery green droppings, discharge from eyes or nares, or sudden death. Those birds that are carriers and used for breeding can pass it to their offspring who may then die in the nest or at weaning or become carriers themselves.


Psittacosis is difficult to diagnose. Screening tests are available through laboratories and new tests are being developed to help diagnose the condition faster and easier. A presumptive diagnosis of psittacosis is made based on history, clinical signs, x-rays, and blood work. If psittacosis is suspected, treatment should begin at once.


Specific treatment and route of administration are left to the avian veterinarian. All birds that have been exposed should be treated or all should be tested and those that test positive should be treated. It is important that the birds be isolated from other birds on the premises. No immunity develops to the disease: reinfection even after treatment and full recovery is possible.


Before a new bird comes into the household, it should have a veterinary examination, a chlamydiosis (psittacosis) screening test, and be isolated for at least six weeks. All birds should be purchased from a reputable supplier who screens for the presence of Chlamydia. These steps will help decrease the risk of bringing an infected bird into the household.

Transmission to humans

The chlamydial organism is capable of being transmitted from birds to humans. It is potentially dangerous for persons who are sick, elderly, or immunosuppressed (e.g. patients being treated for cancer or HIV/AIDS). Because the condition in humans may be misdiagnosed, anyone who is exposed to pet birds and who develops a prolonged case of the flu should seek the advice of a physician and make a point of telling their physician about their exposure to birds.

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