Chlamydiosis (also known as parrot fever, chlamydophilosis, psittacosis or ornithosis) is a disease of birds that can also cause disease in humans. It is caused by Chlamydia psittaci, a germ that is a bit bigger than a virus and a bit smaller than most bacteria. There have been no cases where the parrot chlamydia organism has been transmitted directly between humans.

Birds or people generally contract parrot chlamydia by inhaling particles of infected material shed by chlamydia infected birds. The parrot chlamydia may be excreted in droppings, discharge from the eyes or nostrils or exhaled air. To develop psittacosis infection a bird must initially be exposed to the chlamydia organism through contact with a chlamydia infected bird or its droppings or discharges. It is possible for the disease to be carried by birds in a dormant state and then be activated by some stressing factor such as moulting, extremes in weather conditions (e.g. a cold snap), transportation, changes in husbandry or concurrent illnesses. Some birds may carry the organism for years without showing any clinical signs. There has been a case of a solitary pet bird, seemingly well and isolated from other birds for over ten years, dying from psittacosis. Psittacosis is widespread in Australias wild bird population and is a cause of illness in wild birds.Chlamydia in parrots and birdsClinical signs of chlamydiosis are quite variable and can range from sudden death in apparently healthy birds, to simply showing a lack of energy. Often birds show signs of psittacosis like conjunctivitis, respiratory, liver or intestinal disease. These may include any of the following: lethargy, depression, fluffed feathers, depression, loss of appetite, weight loss, diarrhoea, biliverdinuria (green droppings due to bile pigments), laboured respiration, eye discharge, seizures or neurological symptoms. Some birds may show feather colour change (green to yellow or grey to black). Others parrots with chlamydia may chew at their feathers or bodies, possibly due to discomfort associated with internal organ damage. Species of birds that may be affected with psittacosis include cockatoos, cockatiels, budgerigars, parrots, finches, chickens and ducks.Diagnosisof chlamydia in birds and parrotsBecause clinical signs of psittacosis are highly variable and can be the same as those caused by other diseases, avian chlamydia diagnosis needs to be confirmed by laboratory testing and/or post mortem examination. Common tests done in live birds check for the presence of the psittacosis organism. This is generally done by a PCR test that needs to be sent away to a laboratory and takes two weeks. presence of antibodies in the blood to the avian chlamydia organism. This parrot chlamydia test is done at the clinic and chlamydia results are ready in several hours.It is important to understand that neither these tests, are 100% accurate. A bird may not shed the bird chlamydia organism constantly, in which case there could be a negative PCR test result but the bird could still be infected. Some birds that have been exposed to the psittacosis organism may not produce antibodies against it because it is early in the infection or their immune system is poor. Some birds who have been exposed to the chlamydia organism may have eliminated the virus but still show some antibodies against it. Your Melbourne avian veterinarian can advise you as to which tests to do. Positive avian chlamidia test results, in conjunction with other characteristic parrot chlamydia symptoms, are generally strong evidence of the disease. Sometimes we will recommend treatment in birds with characteristics symptoms even though test results are negative.