Parrot Beak and Feather Disease  

Every now and then, people comment on seeing the odd Sulphur-crested Cockatoo in a mob which has extensive feather loss around the head which sometimes extends to the body. In addition, the beak looks deformed and overgrown.

These sightings are not uncommon and during winter these birds become dependant on backyard bird feeders for their survival.

The condition is commonly known as Beak and Feather Disease or more technically Psittacine Circovirus Disease, after the virus group affecting parrots. While the disease is commonly noted in the Sulphur-crested Cockatoo it is known to affect a large number of the members belonging to the parrot, lovebird, lory and cockatoo families. In addition it has been suspected of affecting some non parrot species including the dove family but this still requires further investigation.

While the name Beak and Feather Disease would suggest that the virus relates only to these tissues it actually attacks the epithelium cells and many other tissues and organs in the body. It has three forms and these relate to the age that the virus affects the birds. In very young birds “neonates” the disease appears as septicaemia, enteritis or pneumonia and death is rapid. Birds at the fledging stage or first feather formation have a less rapid onset of the disease exhibiting signs of depression, diarrhoea, feather abnormalities but still death. The most observed chronic form is seen in older birds usually 6 -12 months of age undergoing their first and successive adult moults with increasing feather deformation and loss of powder down. Excessive beak growth and rotting is more common in cockatoos. Death is not sudden but progressive, taking 6 -24 months from the onset of clinical signs. The bird has a progressive inability to feed and is subject to secondary events.

The virus is spread in feather dust, faeces and crop tissue allowing transfer from adults to young during feeding.

This disease is widespread in the wild population of parrots and the chances of a bird surviving the disease and mounting an immune response depends on the route the virus enters the body and the dose level of the infecting virus. Other factors also play a role such as the age of the bird at the time of infection and if the mother has passed on maternal antibodies.

While the disease usually causes death in the wild some birds have been known to survive if nursed. The issue here is that the virus often persists within the liver and therefore the bird continues to excrete the virus when released back into the wild. Thereby posing a greater threat to other birds it comes in contact with.

Most established populations of parrots can handle the disease and in itself does not pose a threat to the species. However that is not the case for vulnerable parrot species where this disease may be the additional threat which places it into extinction. Hence research is focused on the development of a vaccine to assist the reestablishment of vulnerable species.

Diagnosis of the disease requires a few feathers and a couple of drops of blood to determine the presence and activity of the virus in the bird. A few other diseases can be confused with beak and feather causing the highly visible feather deformations but Beak and Feather is well established in the ACT and would be considered the most likely suspect disease in the majority of cases.