Feather disease, also known as psittacine beak and feather disease (PBFD), is a viral infection that affects the feathers and beaks of parrots. It is caused by a circovirus called beak and feather disease virus (BFDV) that attacks the cells that produce feathers. Feather disease can affect parrots of all ages, but is most commonly seen in young, recently weaned birds between 3-6 months old.
Symptoms
The main symptoms of feather disease include:
- Feather abnormalities – this is often the first sign noticed by owners. Feathers become dull, fragile and may break off or be easily pulled out. New emerging feathers are often twisted or curled.
- Beak abnormalities – the beak may appear to be overgrown, thickened or flaky. Parts of the beak may break off.
- Feather loss (alopecia) – birds start to show bald patches where feathers have fallen out and new ones are not growing back properly.
- Skin lesions – without the protection of feathers, some birds develop dry, crusty lesions on the skin.
- Color changes – infected birds may show odd color variations or darkening on certain feathers.
- Immune suppression – PBFD affects the immune system, making birds more prone to secondary infections.
- Lethargy and loss of appetite – sick birds often become depressed, fluffed up and lose interest in food.
- Diarrhea – some affected birds develop chronic, watery droppings.
- Seizures and ataxia – in advanced cases, neurologic signs can occur if the virus spreads to the central nervous system.
- Death – birds with feather disease deteriorate over weeks to months and the disease is often fatal if left untreated.
Progression of Feather Abnormalities
The earliest feather abnormalities are subtle and involve the feather barbs and barbules. Affected feathers look ragged under magnification. Later, the feathers become brittle and prone to breaking. Established feather disease causes obvious missing or dystrophic feathers. The feather follicles are damaged and unable to produce normal feathers.
Feather loss typically starts on the head, neck and chest areas. As it progresses, bald patches and thinning feathers become more widespread. The wings and tail are often affected last. In some cases, feather loss is incomplete and patchy. Severely affected birds are practically featherless except for some quill shafts sticking out of the skin.
Beak Abnormalities
The beak is made up of layers of keratin, similar to feathers. PBFD causes crusting, flaking and damage to the outer layers of the beak. The beak may appear thickened, brittle or overgrown. In severe cases, the beak is very deformed with large portions breaking off.
It is common for the upper beak to be more affected than the lower. However, both can show abnormalities. The cere (fleshy area at the base) may also appear crusty or thickened. These beak changes are permanent due to underlying damage to the basal epithelial cells.
When Does Feather Loss Start?
The onset of feather abnormalities varies between individual birds. However, there is generally a predictable pattern:
- 3-6 weeks – subtle signs like damaged feather barbs and quills.
- 2-3 months – more obvious feather dystrophy and beak lesions.
- 3-6 months – feather loss starts, often on the head and neck.
- 6-12 months – extensive feather loss and beak deformity.
The course is more rapid in nestlings or fledglings infected at a very young age. Older juveniles may not show symptoms until their first molt, while adult birds can take over 12 months to manifest feather disease.
What Does Feather Picking Look Like?
Feather picking is common in birds with PBFD. The damaged feathers are irritating or itchy, so the parrot pulls them out. This self-mutilation exacerbates feather loss and damage to the follicles.
Picking typically starts on the chest, then spreads to the back, wings and thighs. Birds with feather disease constantly pick and preen at themselves. Their skin often shows signs of trauma like scabs, scratches or wounds from over-preening. Some birds strip all their feathers, leaving bare, inflamed skin behind.
Secondary Infections
Loss of feathers removes a protective barrier and allows secondary infections to take hold. Bacterial and fungal skin infections are common complications of feather disease. Some symptoms of secondary infections include:
- Crusting dermatitis
- Scaly, flaky or reddened skin
- Pus-filled abscesses
- Creamy plaques (candidiasis)
- Skin discoloration
- Foul odor
Secondary infections worsen feathers loss and illness. They are a common cause of mortality in PBFD cases. Proper management of skin infections is crucial when treating feather disease.
How is Feather Disease Diagnosed?
Diagnosis of feather disease requires testing to detect the circovirus:
- PCR test – the most sensitive and accurate method. Detects viral DNA from a small blood sample.
- HAI titer – measures antibodies to the virus in the bloodstream. Less reliable than PCR.
- Biopsy – microscopic examination of feather follicles and beak tissue for virus particles.
- Electron microscopy – direct visualization of the virus from samples.
PCR testing is recommended whenever feather disease is suspected. Skin and feather cytology can help diagnose secondary infections.
Is Feather Disease Contagious?
Yes, PBFD is very contagious between parrots and can spread rapidly in aviaries or multi-bird households. The virus is present in feather dust and dander, crop secretions, feces and on surfaces.
Even birds without symptoms can be carriers and transmit BFDV. Newly acquired birds should be quarantined and tested before introducing them to a collection. Isolating sick birds is important to prevent viral spread.
Prognosis and Outcome
The prognosis for feather disease depends on several factors:
- Age – younger birds have a poorer prognosis.
- Species – cockatoos tend to be more severely affected.
- Viral strain – some strains are more pathogenic.
- Husbandry – poor nutrition and stress worsens disease.
- Secondary infections – if poorly managed.
- Timeliness of treatment – earlier intervention is better.
Mildly affected birds can recover well and regain most feathers with treatment. However, severely diseased birds often succumb to health complications. PBFD shortens lifespan even in surviving birds.
Is There a Cure?
There is no known cure for feather disease itself. However, supportive care and managing complications is critical. Steps include:
- Antivirals – to slow viral replication.
- Immune stimulants – to boost the immune response.
- Antibiotics – to treat secondary skin infections.
- Amino acid supplementation – provides building blocks for keratin.
- Nutritional support – with formulas high in protein, fat and antioxidants.
- Hygiene – keeping the bird’s environment clean.
- Stress reduction – through enrichment and companionship.
- Beak trimming – filing or grinding to manage overgrowth.
With intensive care, some birds can achieve long-term control of PBFD. But they remain infected and relapses are possible during times of stress.
Prevention
Since there is no cure, prevention is critical in feather disease management. Recommended steps include:
- Test and quarantine new bird introductions.
- Isolate any birds showing symptoms.
- Disinfect cages and aviary surfaces.
- Avoid bringing in items from other bird collections.
- Do not allow pet birds to interact with wild parrots.
- Vaccinate chicks of valuable breeding birds.
- Cull birds testing positive for PBFD.
Strict biosecurity measures are necessary to keep feather disease out of a collection. Suspected cases should be handled as if positive while awaiting test results.
Summary
Feather disease is a serious viral infection of parrots that causes severe feather and beak abnormalities. It is caused by beak and feather disease virus that damages the basal epithelial cells needed for normal keratin production. Symptoms include dull, fragile feathers, beak deformities, extensive feather loss and secondary skin infections.
The disease is progressive if left untreated, leading to deterioration and death in many cases. While there is no cure, supportive care and managing complications can allow some birds to stabilize. However, PBFD shortens lifespan and affected birds remain lifelong carriers. Prevention through quarantine, hygiene and vaccination is critical to protect avian collections.