Parrots, perching birds, pigeons, and doves can be susceptible to a disease known as psittacine beak and feather disease (PBFD). It can cause the growth of abnormal feathers and feather loss, resulting in large areas of missing feathers or baldness in the affected bird. This viral disease is highly contagious to susceptible birds and is often fatal. Opportunistic infections may occur in PBFD-positive birds, as their immune systems can be depressed.
What Is Psittacine Beak and Feather Disease?
PBFD is caused by a psittacine circovirus.1 Psittacines are also known as parrots and include macaws, parakeets, cockatiels, cockatoos, lovebirds, and lorikeets. Australian cockatoos were first observed with this condition in the early 1970s.2 Unfortunately, the virus has now spread to over 50 bird species worldwide, including Passeriformes (perching birds) and Columbiformes (pigeons and doves). Once a bird is infected, the disease progresses slowly, producing signs similar to human AIDS. In fact, PBFD is often called “bird AIDS” because the virus depresses the immune system, increasing the bird’s susceptibility to other illnesses and disorders that it could otherwise fight off.
What Are the Signs of Psittacine Beak and Feather Disease?
The circovirus that causes PBFD progresses slowly, so it may take weeks, months, or years before the bird shows any signs of the disease. The first sign that a bird is infected with PBFD is often the loss of powder down feathers, a lack of powder on the beak, and an unkempt appearance. The specialized down feathers produce a talcum-like powder to help with waterproofing and are found in only a few birds,3 including African gray parrots, cockatiels, and cockatoos.
The disease may progress to dead or deformed feathers that may be short, stumped, pinched, or clubbed at the base. The feathers may easily fall out, regrow slowly, or not grow back at all. Beak lesions may appear during any stage of the disease,4 but occur most commonly in birds with advanced disease and chronic feather changes. Overgrowth, cracking, fractures, and infection of the beak are all possible sequelae of the disease. Young birds 6 months to 3 years of age are commonly affected. Once signs appear, most die from the disease itself or secondary infections within 6–12 months.
There are three forms of the disease, each categorized by the age of the bird when it is first infected with PBFD.
|PBFD Forms||Age of Bird||Clinical Signs of Disease|
|Peracute||Recently hatched chicks; neonatal birds||
|Acute||Young birds growing first feathers or pin feathers; nestlings||
|Chronic||Older birds that have survived the acute form of the disease||
What Are the Causes of Psittacine Beak and Feather Disease?
Virus particles are easily shed through feather and skin dander, fecal material, and crop contents of infected birds.
Birds may become infected by encountering the virus through the following routes:
The cloaca (the Latin term for “sewer”) is a single opening in a bird where its gastrointestinal, urinary, and reproductive tracts all convene. Parent birds may pass the virus to their chicks through crop milk during feeding. The crop is an outpouching of the esophagus that stores food and prepares it for digestion. Crop milk is produced by the sloughing of the crop wall, which is rich in protein and fat for newly hatched birds. Dander and feather dust from birds also contain high concentrations of virus particles, which can easily be spread by fomites like shoes, clothing, and other inanimate objects.
How Do I Care for a Bird With Psittacine Beak and Feather Disease?
PBFD is most accurately diagnosed by your bird’s history and clinical signs, as well as the vet taking a blood sample from your bird and testing for viral DNA through polymerase chain reaction (PCR). Feces and feather dander can also be tested with PCR. If your bird has feather abnormalities, a biopsy of skin and feathers may help rule out other causes for the disease, but it is not 100% diagnostic for PBFD. According to the Merck Veterinary Manual, the prevalence of PBFD has decreased since implementing the PCR assay test.
If you buy a new bird, it should be tested for the virus prior to bringing it into your household. Likewise, any birds that you already have at home should also be tested before you introduce your new family member. All PBFD-positive birds need to be isolated or removed from those without the disease because it is contagious and can be easily transmitted to healthy birds. The virus is hardy in the environment, so hygiene and dander control are crucial in limiting its spread. Always take care of isolated and quarantined birds last to help prevent the accidental spread to healthy birds.
Unfortunately, there is no treatment for PBFD, and the disease is usually fatal. Providing as much of a stress-free environment can help, as can supportive care such as warmth and a healthy diet. Humane euthanasia may be considered because the disease is highly transmittable and often results in the death of the infected bird. There is no commercial vaccine currently available for the prevention of PBFD, though research is ongoing.
Frequently Asked Questions (FAQs)
Is psittacine beak and feather disease curable?
Unfortunately, there is no cure for the disease, and it is usually fatal.
Is there a vaccine available for PBFD?
There is currently no commercially available vaccine for PBFD.
Is PBFD contagious to people or other animals?
PBFD is not known to infect humans or other animals.
Psittacine beak and feather disease is a viral disease of parrots caused by an avian circovirus. The disease spreads to healthy birds through direct contact with infected birds and contaminated skin dander and feather dust, feces, and oral secretions. Affected birds develop beak and feather abnormalities and immune system dysfunction. The virus is highly contagious and hardy in the environment. There is no cure or treatment for birds with PBFD, and it is usually fatal. Prevention includes testing all newly acquired birds, isolating infected birds from healthy birds, and implementing strict hygiene protocols.
Featured Image Credit: Daria Nipot, Shutterstock