The first generalized infection caused by any polyomavirus in any species of animal was described in young budgerigars and was called budgerigar fledgling disease (BFD). An avian polyomavirus related to the one recovered from budgerigars has been shown to infect several other species of birds. The clinical changes and progression of disease varies dramatically between budgerigars and non-budgerigar psittacine.

The polyomaviruses that infect birds are not known to infect humans or other mammals. The outcome of a polyomavirus infection in a budgerigar depends primarily on a bird's age when it is infected. Younger birds are most severely affected. In aggressive aviary outbreaks, most infected chicks may die within a several week period.

Chicks that survive the initial phase of an infection can have abnormally developed feathers frequently referred to as French Molt. Budgerigars with abnormal flight feathers are commonly referred to as "runners." Visibly similar feather lesions can be caused by any event that damages the blood supply to developing feathers.

In Europe a more chronic form of the disease is common, while in the United States and Canada an acute form of disease with high mortality is typical.

In some budgerigar flocks, 100 percent of the birds have been shown to have been previously infected. In other more intensively managed flocks, polyomavirus activity cannot be demonstrated in any of the tested birds.

Virus transmission is thought to primarily occur through direct or indirect contact with contaminated feather or fecal dust. Infected budgerigar hens can pass the virus through the egg.

The environmental stability of avian polyomavirus causes a considerable problem in the home or aviary.

Watch for signs of bruising, bleeding and sudden death in chicks.

Watch for signs of abnormal feather development.

Diagnosis

There are several ways to detect polyomavirus in birds. Diagnostic tests your veterinarian may recommend include:

Microscopic examination of affected feathers

Serology (testing for antibodies)

Culture for avian polyomavirus -- a DNA probe-based test (PCR) on choanal and cloacal swab

DNA probe-based test (PCR) on whole blood -- a DNA probe-based test (in situ hybridization) on tissues of birds with suspicious microscopic changes

Treatment

There is no specific treatment for polyomaviruses.

Fluids and supportive nutrition as needed

Several immune system stimulants have been suggested to help the bird eliminate the infection.

Vaccinate to decrease transmission and susceptibility to disease.

Home Care and Prevention

At home keep infected birds and those to which they have been exposed in isolation during recovery. Thoroughly clean and disinfect enclosures, food bowls and non-porous toys and perches. Discard porous (wood, natural fibers, rope, etc) objects that cannot be thoroughly cleaned and disinfected and do not replace them until birds are clinically normal and no longer shedding virus.

Finally, monitor fecal output to insure proper food consumption and digestion on a daily basis.

There are several things you can do to prevent pyomavirus infection. These include:

Vaccination

Reduce crowding and improve air circulation and hygiene.

Keep your bird out of direct or indirect contact with other birds.

Enjoy the bird you have. If you decide to add a new bird, it should be quarantined for at least 90 days and be examined by an avian veterinarian at the beginning and end of quarantine.

Have any new bird vaccinated and tested during quarantine. Quarantine any bird that has been taken from the home or aviary and exposed to other birds before placing it back in the home or aviary.

Use biosecure shipping containers to prevent exposure to avian polyomavirus during transport.