Psittacin Beak and Feather Disease
A virus known for a long time
This disease was first studied in 1975 on Australian parrots. It is caused by a circovirus, which mainly affects Australian parrots. It evolves over several years.
Alteration of feathers and beak
The virus prevents the normal production of keratin by the body, which is the protein that goes into the formation of horny productions: feathers, beak and scales of the legs.
Symptoms start with a deformation of a few feathers after the moult, the new shoots not developing properly. The feathers remain hooded in their sleeves and sometimes have small spots of blood at their base. Little by little, the bird moves around until it becomes completely naked. The cockatoo beak becomes shiny, because the keratin powder which is normally present on its surface is no longer properly synthesized (see photo 1: cockatoo with PBFD) .
The scales of the legs deform and the beak loses its rigidity, until it softens completely and sometimes falls in extreme cases.
In the wild, the bird, unable to fly and feed, dies quickly. In captivity, he can live much longer (several years) with the virus, thanks to the assistance of his master.
This disease also causes an immunodeficiency (attack of the immune defenses) which weakens the bird even more by allowing the appearance of all kinds of other opportunistic infections.
A confusing disease that evolves differently depending on the parrot species
Among the affected birds, many remain healthy carriers of the virus without developing the disease. Despite everything, they are contagious.
The parrots most susceptible to this disease are Australian parrots, such as all varieties of cockatoo or eclectus. A damage in a cockatoo is very serious because it generally leads to the death of the animal.
South American parrots (Macaws, Amazons, Pionus, etc.) are much more resistant and generally eliminate the virus spontaneously after a few months.
The sensitivity of African parrots (Gray Gabon for example) seems intermediate: very few adults affected develop the disease, most remain healthy carriers. On the other hand, this virus is devastating for young Grays between weaning and 6 months, because they can die suddenly in two to three days without any treatment being possible.
Parakeets (wavy, cockatiel, lovebirds …) are also sensitive, but most often make attenuated forms (see photo 2, budgerigar with PBFD) . They can however play the role of virus reservoir and transmit it to parrots.
There are PCR tests that can detect the DNA of the virus in the bird’s blood or from a tip of the pen. These tests have been known for a long time and their results are reliable.
A positive test does not mean the same thing depending on the species of parrot:
A positive cockatoo unfortunately has every chance of developing the disease.
A positive adult African parrot (Gray, Senegal, etc.) that does not show symptoms remains generally positive, rarely develops the disease, but remains contagious for its congeners and young. However, it is possible that it will clear the virus spontaneously over time.
A positive South American parrot (Macaw, Amazon, etc.) only very rarely develops the disease. It is likely that it will spontaneously clear the virus after a few months. It is therefore useful to repeat the PCR test after 4 to 6 months after a positive test to check if the bird is still a carrier.