psittacine beak and feather disease (pbfd)

PSITTACINE BEAK AND FEATHER DISEASE (PBFD)
Psittacine beak and feather disease (PBFD) is one of the most common diseases seen in
young parrots here at the BVC. Although many birds can be affected, including
cockatoos, cockatiels, lories and lorikeets, parakeets, lovebirds, electus parrots, macaws,
amazons and even canaries, the African grey parrot is the most commonly affected
parrot presented at the BVC. This is probably over-represented as a species due to its
popularity as a pet in the UAE.
So, what is PBFD?
PBFD is a viral disease cause by a very small
circovirus. It is very stable in the environment
and very resistant to many disinfectants,
meaning it can remain infectious in the
environment for months and possibly even
years.
The virus is shed in feather powder and faeces of infected birds for several months after
infection. Birds can become infected by inhalation of contaminated feather dust or oral
ingestion of fresh or dried faeces. Due to its tough nature and resistance, the virus can
be easily spread by people having contaminated feather dust on their clothes, as well as
through contaminated food, food utensils or traveling boxes or cages. Females can also
transmit the virus through their eggs to their young.
In general, birds over 3 years of age seem to be less susceptible to PBFD. The disease
seems to thrive in young birds with poorly developed immune systems. However, birds
of any age can be affected by PBFD.
How can this disease affect my bird?
The virus targets dividing cells, and therefore mainly immune tissue, skin and feathers.
This in turn causes immunosuppression and, as the name suggests, beak and feather
abnormalities.
Four different presentations of the disease have been described, depending largely on
the age of the bird at the time of infection. Many young birds presenting with PFBD are
often also malnourished, which will also affect the course of the disease. However, at
present the disease has almost always proved fatal.
1. Peracute: seen mostly in newly hatched birds. Whilst this form is common in
breeding aviaries, you as a pet owner are unlikely to come across it. Most birds
die suddenly without showing any signs.
2. Acute: affecting birds up to 1 year of age, and the most common form seen here
at the BVC. The birds are often depressed, anorexic, weak and have diarrhoea.
Immunosupression may lead to secondary complications, a common one being
pneumonia. Feathers may be affected, often presenting as loss of feather powder.
This can be obvious clinically in birds with black beaks: instead of having a
white powdery covering the beak becomes very shiny and black. Growing
feathers may be malformed or feather colour changes may occur. In African
greys this usually presents as red body feathers
3. Chronic: occurs mainly in older birds, and presents as feather loss and feather
deformity, getting worse from moult to moult. Feather changes are often
followed by secondary complications due to immunosuppression. As the disease
progresses the beak and nails can become brittle and of poor quality. The disease
is always fatal but this can be several years after the initial clinical signs.
4. Clinically Inconspicuous form: mostly in older birds that have been infected but
not affected by the virus. They will continue to shed the virus and be a constant
source of infection to other birds.
How can I find out if my bird is suffering from PBFD?
The diagnosis of PBFD is achieved through a
blood test. A small drop of blood is collected,
usually from the soft tissue between the joints of
the toes, and sent to a specialised lab in South
Africa. A very sensitive method called a
polymerase chain reaction (PCR) is used to
detect virus DNA in the blood of the bird. This is
the most sensitive test available for diagnosis of
PBFD and is available to BVC patients.
Collecting the blood sample takes a few seconds
and is minimally invasive.
Can we treat PBFD?
Unfortunately, birds with clinical signs of PBFD have invariably died. Treatment is
largely supportive, in order to help the bird to try and clear the virus on his or her own.
The supportive treatment has 2 main aims:
1. To help the immune system fight the virus: this is achieved through vitamin
supplementation, keeping the bird hydrated through subcutaneous or oral fluids,
addressing the nutritional status of the bird by administering specially
formulated bird diets via syringe or crop feeding, and keeping the bird warm and
comfortable.
2. To treat any secondary infections using antibiotics and antifungals.
Current research is focusing on the use of avian interferon as a treatment option for
PBFD. Early reports are promising, but further research is necessary to determine
success rates. This latest treatment option is available at the BVC, and consists of daily
intramuscular injections of the interferon for 90 days.
What can I do to avoid PBFD?
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Purchase birds from a pet store that has high standards and tests all its birds for
PBFD prior to selling them. Official paperwork should accompany any bird that
is said to be PBFD negative.
If your bird has recently died of PBFD, remember to thoroughly disinfect the
environment and any food bowls, cage or carriers prior to introducing a new bird
into the house. It is also advisable to wait 3 months or more prior to introducing
the new bird. Remember though that the PBFD virus is notoriously resistant and
even with these measures the virus may survive in the environment for a long
time.
Consider a pre-purchase veterinary examination including a PBFD blood test.
Remember that you can carry the virus on your hands or clothes if you have
been with an infected bird (visiting a pet shop/souk, visiting a friends bird, etc...)
Written by Nick Terraz © Copyright 2011 by The British Veterinary Centre