Psittacine Beak and Feather
Disease (PBFD)


Psittacine Beak and Feather Disease - The virus causing this disease is a member of the Circoviridae. The molecular structure of the genome of the virus is roughly a 2,000 base, circular, single stranded DNA. PBFD virus has a strong resemblance to Porcine Circovirus as well as to a number of plant viruses such as the Banana Bungy virus.

The disease is thought to be specific for psittacines and all psittacine species should be considered susceptible. Parrots known to be particularly affected by PBFD include, but are not limited to, Cockatoos, Macaws African Grey Parrots, Ringneck parakeets, Eclectus Parrots, Lovebirds.

Causes fatal infections, primarily in young birds. Older birds may overcome the disease with few lasting affects. Some believe that these surviving birds become carriers able to shed the disease at a later date. Others believe that a percentage of birds are able to eradicate the disease from their system leaving them with a natural immunity that can be passed on to their offspring.

The virus that causes PBFD can also affect the liver, brain, and immune system causing diminished resistance to infections. Consequently premature death usually occurs from these secondary bacterial, fungal, parasitic, or viral infections.

Transmission: Transmission of the virus from one individual to another is primarily through direct contact, inhalation or ingestion of aerosols, crop-feeding, infected fecal material, and feather dust. The virus can also be transmitted via contaminated surfaces such as bird carriers, feeding formula, utensils, food dishes, clothing, and nesting materials. The viral particles, if not destroyed can remain viable in the environment for months, long after the infected bird is gone.

Symptoms include irreversible loss of feathers, shedding of developing feathers, development of abnormal feathers, new pinched feathers, and loss of powder down. Other possible symptoms include overgrown or abnormal beak, symmetrical lesions on the beak and occasionally nails.
Immunosuppression, rapid weight loss, and depression are also possible in later stages of the disease.
Secondary viral, fungal, bacterial or parasitic infections often occurs as a result of diminished immunity caused by a PBFD viral infection. Additional symptoms not mentioned above including elevated white cell counts are generally due to secondary infections and may not be directly related to PBFD virus infections.

Prevention: Strict isolation of all diseased birds to halt the the spread of the disease. DNA testing of all birds of susceptible species to rule out latent infection. DNA testing of aviary equipment and environment to test for possible contamination.
Treatment: No known treatment. Experimental vaccines are being developed.
Diagnosis: Skin biopsy, surgical biopsy of feather and shaft, or PCR testing of blood, swab, and feather samples.

PBFD should be considered in any bird suffering from abnormal feather loss or development. A biopsy of the abnormal feathers including the calimus (shaft) of the feather can be examined for signs of virus. However, since the PBFD virus does not affect all feathers simultaneously this method of evaluating a sample may have a high degree of error. Additionally, birds with PBFD can have normal feathers and the PCR test is the most effective method available for detecting the virus in birds before feather lesions develop.

Some birds infected with the virus, test positive, but never show clinical signs. Other birds which test positive may develop an immune response sufficient enough to fight off the infection and test negative after 30-90 days. Therefore, it is recommended to re-test all PBFD positive birds 60-90 days after the initial testing was completed. If the second sample remains positive, the bird should be considered permanently infected and can be expected to show clinical symptoms of the disease.
Sample: To test an individual bird a whole blood sample is recommended in conjunction with a cloacal swab or feathers (especially abnormal or suspicious-looking feathers) when possible. If the sample tests
positive the bird should be placed in quarantine and re-tested after 4-6 weeks. If the bird tests negative the second time a third test after 4-6 weeks is recommended.

Post-mortem samples include liver, spleen, kidney, feather samples in a sterile container; postmortem swabs may also be submitted.

Environmental testing using swabs of aviaries, countertops, fans, air-filters, nest-boxes, etc. is extremely effective in determining the presence of PBFD DNA in the environment.

*It is recommenced to submit both a whole blood and cloacal swab sample for analysis when possible.
Handling: Prior to shipping samples should be stored at 4 C. (refrigerator). Samples must be shipped in a padded envelope or box. Samples may be sent by regular mail, but overnight is recommended.
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