Psittacine Beak and Feather Disease (PBFD) :
(PBFD) is a contagious, fatal viral disease that affects the beak, feathers, and immune
system of birds belonging to the Psittacidae family. It was first recognized in 1975 by veterinarians in Australia, where the
disease affects wild birds. Although birds showing signs of disease usually die, it is common for birds to be exposed to the
virus, develop a mild infection, and recover.
Birds at Risk:
:PBFD has been diagnosed in over 40 species of psittacines, mostly in Old World members of the parrot family. PBFD is seen
more often in cockatoos, but Eclectus parrots, lovebirds, budgies, and African grey parrots are also affected.
Most birds diagnosed with psittacine beak and feather disease are under 2 years of age.
Causes:
PBFD is caused by a DNA virus that affects the cells of the immune system and those that produce the beak and feathers. The
virus is a circovirus, which is one of the smallest viruses known to cause disease.
Transmission:
PBFD is extremely contagious. Large amounts of the virus, which can become airborne, are found in the droppings, contents
of the crop, and the feather dust of infected birds. The feather dust is easily dispersed and can contaminate food, water, cages,
clothing, and other areas of the environment. PBFD is thought to be transmitted by inhalation or
ingestion of the virus. The virus may be transmitted in utero from the female bird to the egg.
The incubation period can be as short as 3-4 weeks.
to several years, depending upon the amount of virus transmitted, the age of the bird, the stage of feather development, and
the health of the bird's immune system.
Signs of PBFD:
There are both acute and chronic forms of the disease.
Peracute/Acute Form: The peracute and acute forms occur in very young birds, and may begin with signs
unrelated to the beak or feathers. Affected birds are often depressed and regurgitate due to crop stasis. They may develop a
diarrhea-causing enteritis or pneumonia, and die without displaying any lesions of the feathers or beak. Called the
peracute form of the disease. In the acute form, juveniles losing their down and developing feathers may have lesions on the
feathers, including circular bands around the feathers which constrict the feather at its base. These feathers are often loose,
break easily, may bleed, and are very painful.
Common Signs of Psittacine Beak & Feather Disease
Acute Form Chronic Form:
Depression
Regurgitation, diarrhea, Loss of appetite and weight, Abnormal feather development
Death
Loss of feather dust and powder, Abnormal feather development
Abnormal growth and deformities of the beak, Necrotic beak and oral lesions
Secondary infections,.Death in months to years
Chronic Form: More common in older birds, the powder-down feathers are often the
first feathers affected. The feathers are fragile and fracture easily, have constricting bands, may hemorrhage, and may be
discolored, deformed, or curled. As the feather follicles are damaged, the bird will soon be unable to replace feathers, and the
primary, secondary, tail, and crest feathers are lost. Bare skin is exposed, and the normal feather dust is not found on the body
or the beak, where it normally accumulates due to preening. Feather abnormalities, " dystrophic feathers," may
not appear until the first molt after infection, a period up to 6 months.
The beak may develop irregular sunken areas. Brown necrotic areas may be found inside the upper beak, and the beak may
elongate, become deformed, and fracture. Secondary beak and oral infections often occur. The nails can also be affected.
Mucus in the droppings, or a green tint to the droppings may occur. In some birds, the liver will be affected, and liver failure
may be the cause of death.
Birds with the chronic form of the disease may live for months to years before dying of a secondary infection.
Diagnosis:
The review of the medical history, presence of clinical signs, and observations during the physical exam support the
diagnosis of PBFD.
The diagnosis may also be confirmed by a PCR (polymerase chain reaction) test on whole blood or biopsy samples from the affected bird.
The test detects the presence of the virus. This test may be used on swabs of surfaces in the environment to detect contamination.
False positive and false negative test results can occur. Healthy birds with a positive test result should be retested after 90 days. If they still have positive
test results, they should be considered carriers of the virus. If the retest is negative, the bird may have eliminated the virus,
and become immune.
How is PBFD treated?
There is no specific treatment for PBFD. Supportive care - good nutrition, supplementary heat (incubator), beak
trimming, and treatment of secondary infections can be offered. The disease, however, is progressive, and very few birds
recover. Euthanasia may need to be considered for birds with severe and/or painful signs. Birds who die a natural death
usually succumb to a secondary bacterial, fungal, or viral infection despite treatment, since their immune systems have been
compromised. Most birds die within 6 months to 2 years of developing the disease.
prevention and control :
Birds should be purchased from suppliers with disease-free birds. New birds coming into facilities
should be quarantined and tested. Repeat testing in 3-4 weeks to allow for the incubation period is
recommended. Infected birds should be isolated and removed from breeding programs. Juvenile birds
should be housed separately from adults. Bird owners need to understand that if they handle other
peoples' birds, it may be possible for them to bring the virus into their home and infect their birds. Good
hygiene and sanitation should be used. There is no known disinfectant that kills this virus.
In Australia, a killed vaccine has been developed which can protect unexposed birds; it can cause more
severe disease in birds already showing signs of PBFD. Birds should be vaccinated as soon as two weeks age.
The vaccine should be boostered after one month.
