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Psittacosis (also known as "parrot fever", ornithosis or chlamydiosis) is a widespread disease caused by an organism called Chyamydia psittaci. The pet bird owner may be increasingly aware of the prevalence of psittacosis, but that is believed due to improved diagnostic methods rather than actual increase in disease incidence.


Transmission of psittacosis is primarily by inhalations of infected dust from droppings or feathers, and is enhanced by close contact with sick birds that are shedding the organism. For this reason, the disease is most often seen in birds that have been recently imported, housed in pet shops, or boarded with other birds. Birds tend to shed the organism under conditions of stress. Birds do not have to show symptoms of disease in order to transmit clamydia.


There are no specific signs that are characteristic of psittacosis. Some birds may show general sick, symptoms-lack of appetite; weight loss; depression and listlessness; watery, green droppings; discharge from eyes or nares; or even sudden death. Of course, these signs may be related to disease other than psittacosis. Many birds carry the chlamydidal organism but do not show any signs of disease under stable conditions. These birds may become sick after some stressful occurrence, or breeding birds may pass the organism on to their offspring, which may die in the nest or at weaning. Young birds are more susceptible to a severe debilitating infection than are adult birds.


Positive diagnosis of chlamydiosis in the live bird is sometimes very difficult, depending on the species, length of time since exposure, and general condition of the bird. In addition to having the capability of producing disease on its own, chlamydia undermines the immune system and opens the body to a host of other pathogens: thus, bacteria or viral disorders may be occurring at the same time. Because it is far easier to diagnose a bacterial problem, the chlamydiosis may be missed.


Some chlamydiosis screening tests are available through out laboratory services, and new tests are being developed that will help your veterinarian diagnose psittacosis in his clinic. There is no single diagnostic test in the live bird that can absolutely show the presence of chlamydia in all cases. Your avian veterinarian may be able to make a presumptive diagnosis of psittacosis based on history, clinical signs, X-rays, blood work or other diagnostic methods. If psittacosis is suspected, treatment should begin at once, even as confirmatory tests are being run. (There is now a new blood test that will identify if the bird is producing protective antibodies against the organism).


If psittacosis has been diagnosed in one of your birds, your veterinarian may recommend treatment of all exposed and potentially infected birds, or exposed birds may be tested first and treatment limited to those that test positive. To reduce the spread of the disease, it is imperative that the patient be isolated from other birds on the premises.


The success of treatment depends upon the species, age, and presence of concurrent infections and immune status of the patient. Medication can be given by direct oral administration, by infection, as medicated pellets, or mixed in soft foods. Water medication, such as an over-the-counter product, is not an effective treatment.  The specific medication and route of administration are left to the discretion of the veterinarian. The treatment period will last a minimum of 45 days. Depending on the condition of the patient, other forms of supportive therapy may be necessary. There is no immunity to the disease, and birds are susceptible to re-infection even after full recovery or previous treatment.


During treatment the owner must:


  • Clean the premises with a disinfectant recommended by an avian veterinarian to kill the organism.

  • Exercise caution in handling of bird droppings.

  • Keep circulation of feathers and feather dust to a minimum.

  • Separate and isolate any other birds that may show beginning signs of disease.

  • Avoid contact with birds by elderly, pregnant, sick or very young persons, especially in the early stages of the treatment.

  • Remove all mineral supplements containing calcium, as calcium interferes with the medication.

  • Reduce stress in the bird's environment. Further testing of affected birds is advised following therapy, as the treatment may not be fully effective, even though clinical signs abate.

  • In extreme cases, especially those involving aviaries with significant losses, euthanasia may be necessary for individual birds if multiple tests indicate a persistent infection after repeated treatment attempts.

The following recommendations help prevent psittacosis in flocks or households:


  • Take all new birds to a qualified avian veterinarian immediately after purchase for chlamydiosis screening tests.

  • Buy birds from reputable suppliers who screen for the presence of chlamydia.

  •  Isolate and quarantine all newly acquired birds for a period of at least six weeks.

  • Periodically monitor breeding flocks for chlamydiosis.

--Reprinted from 1991 Association of Avian Veterinarians Education Office

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