Psitaccine beak and feather disease (PBFD) is a viral disease that infects birds of the family Psittacidae (parrots). The disease influences the development of feathers, beak and immune system. The disease is fatal in many cases. PBFD is caused by Circovirus that infects and kills cells of feather pulp and beak. The virus also compromises immune system, which is the reason why parrots often die of secondary infections caused by viruses, fungi and protozoa. The disease can affect all species of parrots, however it is more common with cockatoos, cockatiels, macaws, african greys, rose-ringed parakeet, eclectuses, lovebirds and budgies. Acute illness affects especially young birds (up to 2 years). It is fast progressing disease and often fatal. The disease progresses especially fast in birds that are hand fed. Only minor symptoms may manifest in case of chronic illness. These are often overlooked and can last several years before the bird dies. Through that period chronically ill birds can spread disease to other birds or their offspring. It is therefore important to detect the presence of disease as soon as possible before it spreads through the bird flock and offspring. Several researches show that the disease is ubiquitous and roughly 5% of birds are infected; however in some cases these percentages can be much higher.
The main symptoms of PBFD are:
Loss of large amount of feather that do not regenerate
Growth of abnormal feathers
Growth of new feathers in abnormal directions
Loss of feather down
Uncontrolled and irregular growth of a beak
Types of developed symptoms depend on the disease progress. In later stages of the disease symptoms like loss of appetite, diarrhoea, vomiting, loss of weight and depression can occur. Parrots can die after one month or only after several years.
Spread of the disease and prevention
PBFD is transmitted through the bird to bird contact and not from / to human or other animals. It is usually transmitted by direct contact of two birds, breathing of aerosol, wing dust, secretions, sperm, eggs and food. The virus can also be spread with infected food, water containers, nesting material, poles, other cage equipment, ect. It is often carried from asymptomatic mother or father to the offspring or infects eggs before they are laid. PBFD stays present and active for months after the infected bird was removed. Thus the entire place has to be properly cleaned and disinfected. There are several disinfectants available on the market that will destroy the virus. It is important that the infected bird is isolated as soon as we suspect the illness, which prevents further spread of the virus. The bird should be tested for presence of the virus and the rest of birds being in contact should be tested in case of positive result. It is also recommended to randomly test birds from the rest of the flock, which will help efficiently and quickly limit the development and spread of the disease.
There is no cure or vaccine for the disease caused by PBFD. Because there is no cure or vaccine for the disease it is important to notice the disease at an early stage as this is the only way to stop the disease from spreading.
There are several tests that can efficiently proof the disease. The most frequently used method is polymerase chain reaction (PCR). The method is used to detect viral DNA in blood, faeces or feather pulp. The method is based on amplification of viral DNA in a sample and is non-invasive and therefore friendly for a bird and the owner. Another method used for detection of virus is immunological testing based on ELISA. The method tests host’s immune response; however it has several disadvantages such as: the immune response can vary for bird to bird, the antibodies are present long after the disease is cured and it is less accurate than PCR.
Sampling, storage and shipment of samples
The PCR test can be made with the use of blood or feather pulp. It is important that blood and feathers are fresh. It is recommended to send both samples at the time.