Diseases and conditions

PBFD / Psittacine Beak and Feather Disease

This disease is caused by a circovirus and is most commonly diagnosed in members of the parrot family. Birds are infected by ingesting the virus through the beak or by inhalation. The virus particles are often found in the droppings and feather dust of infected birds and are highly resistant to cleaning agents.

 

The disease manifests itself in different forms.

There is the acute form. This is most common in birds that have already been infected at a young age. The first signs of the disease are seen when the young birds lose their down feathers and start developing adult plumage. The growing feathers die, break, bend or bleed from the shaft. Feathers can also fall out prematurely if they do grow to full length. Besides abnormalities in feather growth, birds can also experience lethargy, loss of appetite and delayed emptying of the crop. They can die within one to two weeks.

 

The chronic form of PBFD causes the plumage to deteriorate. The virus influences the development of new feather. The first abnormalities are usually seen in the down feathers, because these are continuously moulting. The large flight feathers and contour feathers become more deformed with each moulting period. The feathers that do come through stop growing prematurely. They may have an abnormal shape or are fragile and break easily. It is also possible that only the colour of feathers show abnormalities in the first stage. If a bird lives with the disease long enough, it will eventually become bald.

Problems can also affect the beak; it may elongate, break and the mucous membrane in the oral cavity may become infected or the cells may even die off.

 

Besides the effects of the virus on the plumage and the beak, it also causes a weakened immune system. As a result, infected or sick birds are much more susceptible to a range of other infections and will become sick earlier in less than ideal conditions.

 

In addition to birds with obvious signs of the disease, there are also those that are carriers. These birds contain the virus and can excrete it, infecting other birds. They may show no signs of the disease themselves. They can, however, develop the disease in case of a malfunctioning immune system. For instance when they have a different illness, have nutritional shortages or in case of stress.

 

Diagnosis

The virus can be seen by testing the blood. Birds with feather or beak abnormalities that also test positive in a blood test have an active PBFD infection. Birds that don't show any symptoms of the disease but test positive can either be a carrier or have recently been infected with the virus and do not show any signs yet. Some birds manage to get rid of the virus after being infected because their immune system has an effective response. For this reason, birds that were tested positive without any clinical signs should be tested once again after 90 days. They may then test negative.

PBFD-positive birds must always be kept separate from healthy birds, particularly from young parrot species. People who come into contact with sick birds should also be very aware that the virus can easily be transmitted by handling the bird or by feather dust.

Infected birds can pass the virus on to their young. They can already be infected while still inside the egg or the parents can infect their young when feeding from the crop.

 

Treatment

 

There is no specific treatment for the virus itself. A sick bird can survive longer if supportive care is given and no secondary bacterial or fungal infection occurs. Excellent nutrition and hygiene are therefore extremely important.