This disease is highly underestimated among breeding farms because the PBFD test is not routinely performed on incoming or outgoing birds.

 

The latest:

 

1) All psittacidae can contract this disease, regardless of age (although infected birds are predominantly between 0 and 3 years of age).

2) The viral agent responsible for the infection has only recently been discovered thanks to the development of a specific test.

3) Many birds (including chicks) in captivity and in the wild have been infected (approximately 20% of Australian cockatoos are contaminated). Not all birds show signs of the disease but remain healthy carriers with a “dormant” virus.

 

4) The absence of feather anomalies does not mean that a bird has not been infected.

 

 

For more information:

A - Aetiology

This infection is due to the smallest known virus in birds (Circovirus of the family of Circoviridae, a non-enveloped virus of 15 nm* diameter). Antigenic variants have been found in pigeons, doves and ostriches.

 

This disease was first described in 1888 in Australia and studied clinically in the 1970s in Australian Cockatoos.

 

The explosion of the international bird trade appears to be the most plausible explanation for its global expansion.

 

(*) a nanometre equals one-millionth of a millimetre.

 

B – The main signs to recognise the disease are the following:

 

- Abnormally large loss of feathers (especially loss of primary wing and tail feathers or feathers that fall off easily).

- Presence of abnormal feathers (tapered, twisted, spun feathers and stems with clots), often accompanied by a powdery look to the duvet and contour of feathers.

- The bird no longer loses the sheath of its feathers after several weeks.

- Discoloration of feathers (presence of a red colour on normally grey feathers, yellow feathers when they should be green)

- Blood clot at the base of new feathers.

- Beak anomalies (elongation of the beak, necrosis of the palate with or without ulceration in very advanced cases).

 

C - Incubation and transmission

 

THE DISEASE IS HIGHLY TRANSMISSIBLE AND CONTAGIOUS BETWEEN BIRDS.

 

There are multiple means of transmission: feather "powder", droppings, eggs, utensils used to feed the birds, humans, clothes.

 

Before the appearance of "visible" signs, the incubation period is highly variable: from 3 to 4 weeks to several years depending on the age of the bird; the initial viral strength at the time of contamination, the stage of plumage development and the defence capacities of the bird’s immune system.

 

Stress (e.g., resulting from a change of venue) can trigger onset of the disease.

 

D - Development

 

When PBFD emerges, its development can take several forms:

 

• Rapid development: the bird dies quickly after the appearance of abnormal feathers and most often a general infection (septicemia). This active form of PBFD especially affects chicks.
• Acute development: initial signs are a loss of weight, diarrhea, congestion in the crop, and a radical change in the look of feathers (the typical case is that of chicks when their first feathers emerge).
  
• Chronic development: progressive appearance of feather anomalies throughout the moulting period such as twisted or curved feathers. Birds in this situation very often retain a strong appetite and normal energy level.
  
• Some of these birds can "heal spontaneously" (there have been published cases among parakeets and lovebirds).

At any stage of development, regardless of the type, secondary infections can occur: bacterial or fungal infections ("mushrooms").

 

E - Prevention

 

The first step in prevention is to strictly isolate the contaminated or suspect specimen.

 

All equipment or objects that may have been contaminated by the bird or are used for its daily care should be tested to see if they are infected.

 

It seems that this virus is able to resist many disinfectants. Furthermore it is able to survive a long time in the surrounding environment.

 

F - Diagnosis

 

Your vet can confirm the diagnosis with an examination from a specialised laboratory (via a PCR test from damaged feathers, blood or a swab of the environment). The sensitivity and precision of this test enables us to know whether the bird is "temporarily" infected or if the infection is active.

 

G - Treatment

 

No specific treatment is currently available. Immunostimulants have been attempted with varying results. For several years, a vaccine has been under development.

 

H - Recommendations when purchasing a parrot

 

We highly recommend that buyers (mainly for African grey parrots and all cockatoos) to obtain a veterinary certificate stating that the bird was PBFD-negative at the time of purchase. The incubation period can last up to 4 weeks; we therefore recommend that you repeat the test 30 days after purchasing the bird to confirm its health.

 

If you cannot obtain this certificate and you still buy the bird, we recommend that, immediately after purchase, you have your veterinarian perform this test.

 

 

The "Avian polyomavirus" article provides useful complementary information.

 

Read also Dr J.-F. QUINTON’s PBFD page

It is essential to consult your veterinarian to undertake a diagnosis and follow-up with an additional examination.