Rose-ringed parakeets of Amsterdam

Psittacine Beak and Feather Disease (PBFD) is a viral infection that is spread easily through feathers and feces.  It affects parrots and other psittacine birds and causes the loss of feathers, usually on the chest or thighs. . In some birds, such as Eclectus, king parrots, and lorikeets, the early signs may be a change in color, with affected feathers showing streaks of white, yellow, or black. Cockatoos and parrots often show loss of the powder down first since powder down is replaced often; it may take a few molts to see changes in coverlets and other feathers. With time, the feather loss involves the wings and the rest of the body.  Early in the infection, feathers may grow in to replace the missing ones. These regrown feathers are abnormally-shaped and easily break at their bases.  As the infection progresses, new feathers do not grow and old ones are not replaced. Infected birds may show excessive abnormal growth of the beak and toenails.  The beak and nails curl in unusual shapes. The beak and nails may flake, crack, and develop soft areas that are weak and may break. Yeast and other infections may develop in cracks of the beak and nails. Beaks can become so severely affected that the bird can no longer feed on its own.

PBFD-infected birds are more likely show other signs of illness because the PBFD virus weakens the bird’s ability to fight infections.  The disease also has a general immunosuppressive effect on the bird, clearing path for secondary systemic viral and bacterial infections which are usually the cause of death, not the PBFD virus itself.

Sometimes the first sign of the disease is weakness, sleeping a lot, poor appetite, and diarrhea and vomiting.  These signs are much more common in very young birds, particularly those still in the nest, rather than adult birds.  Death can happen within 2 to 4 weeks of infection if the PBFD virus overwhelms the immune system of young birds. This rapid form of infection is rare. It is much more common for the initial infection to be overlooked and only detected when feather loss or changes to the beak and nails are seen.  This chronic form of PBFD infection is usually noticed after the first molt as new feathers are deformed or fail to grow.

Nestlings and other young birds are more easily infected with PBFD virus and often develop more severe signs of disease than birds infected as adults.  Adult birds often may recover from the infection and not show any outward signs of the PBFD virus.  Unfortunately, once infected an adult bird will shed the virus in its feathers and its feces for the rest of its life, and will pose a threat to uninfected birds.