Psittacine Beak and Feather disease is a highly contagious viral disease occurring in birds. Cockatoos, African Grey parrots, Senegal or Meyer Parrots, Ring Neck Parakeets, and Lovebirds are very susceptible. This disease rarely occurs in Macaws, but they can become more susceptible to it when the environmental contamination is high. Young Macaws contracting this virus will typically develop anorexia and chronic regurgitation.

The virus is transmitted by direct contact with infected birds or through contamination of water/ feeding bowls or equipment. The virus can be found in faeces, feather dust or crop content. The virus is extremely resistant and it is able to survive in the environment for several months.

Birds often become infected with the virus at a very young age. The hatchlings may develop the acute variant of Psittacine Beak and Feather disease. The clinical signs of the acute disease are poor appetite, crop stasis and diarrhoea. These birds typically die within a few weeks. The minimum time frame between exposure and signs of disease is 21-25 days, but the incubation time is often much longer, from months to even years, for birds to show signs of illness.

Adult birds show feather dystrophy, where the growing feathers get damaged, resulting in progressive baldness. The baldness worsens with every moulting.

Birds showing early clinical signs of Psittacine Beak and Feather disease often present with loss of the delicate powder down feathers and a shiny beak. The regrowth of feathers can be sparse, or the feathers may retain their sheaths, change in colour, or be deformed. The baldness is especially prominent around the ear opening and the beak. These clinical symptoms often develop in birds less than one year of age. The growth of the beak can also be affected by the virus, resulting in abnormal, cracked, or flaky beaks.

Psittacine Beak and Feather disease causes severe immunosuppression, which weakens the bird’s immunity and makes them more susceptible to other diseases, such as bacterial infections. Birds suffering from Psittacine Beak and Feather disease are therefore more prone to recurrent infections, especially infections of the respiratory and intestinal tracts.

Birds showing chronical clinic signs (especially abnormal feathers) should be euthanised. Birds that appear healthy but test positive for Psittacine Beak and Feather Disease can shed the virus and will develop health problems later. Birds may become carriers of the disease. A carrier state means that the bird does not show clinical signs but they can transmit the disease to other birds.

Testing can be conducted. Most commonly, a PCR test is run on a blood sample of a live bird. In some cases, testing may also be performed on feather or skin samples, or a swab from the internal organs of a deceased bird. Birds that test positive on PCR but have no clinical signs should be kept in strict quarantine and should be retested after three months. There is no cure for this virus, like human immunodeficiency virus (HIV). It is therefore advisable to euthanise a bird that tests positive.

When you purchase a new bird ensure that you use a reliable supplier who provides a Psittacine Beak and Feather Disease free certificate with each bird. Practice good quarantine protocol when you get a new bird. Keep new birds as far away from birds already present in your home as possible until the test results are returned. Never place new birds together with resident birds.

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Sources:

• BSAVA Manual of Psittacine Birds, second edition Harcourt-Brown N, Chitty J, eds.
•  BSAVA Manual of Avian Practice, Chitty J and D Monks, eds., 2018

Psittacine beak and feather disease, the lurking epidemic, Dr D. Elliott, http://www.birdandexotic.co.za/News/entryid/1054/psittacine-beak-and-feather-disease-the-lurking-epidemic