Bird - Polyoma Virus Infection

General information

The polyoma virus of pet birds belongs to the family Papova virus. Polyoma virus can cause benign feather lesions in birds (the so-called French molt) or sudden death. It is also known as budgerigar fledgling disease as infection is more common in these birds.

How do birds get polyoma virus infection?

It is not fully known how the virus is spread. Infected but asymptomatic adult birds intermittently shed the virus through feather dust, droppings, eggs, and crop milk used to feed offspring. It is unknown how long it takes from the time of infection until death (if it occurs); however, death may occur anywhere from 15 days after birth (eg budgerigars) to 140 days (e.g. larger parrots).

What are the signs of polyoma virus infection?

There are different strains of the virus which can cause different clinical signs. Some birds (generally budgerigars) recover from the infection but are left with abnormal or absent feathers (French molt). The area of feathering affected is indicative of the age at which the bird was infected. French molt may also be caused by Circo virus (PBFD). Affected birds should be regarded as being lifelong viral carriers and so should be culled out of an aviary. Other birds (especially non-budgerigars) die quickly with no clinical signs. Still others may show abdominal enlargement, haemorrhage (bleeding) areas under the skin, and tremors. Mortality (death rate) can be high, reaching 100% in birds less than 15 days old. Birds that recover probably remain carriers of the virus and can shed it despite not showing signs of illness.

How can I tell if my bird is infected?

Birds, especially baby birds, that die quickly should be examined by a veterinary surgeon. Both sick and healthy birds can be tested using a specific DNA probe of a cloacal swab, easily obtained by the vet.

My bird is healthy. Should he be tested?

This can best be decided by your vet. However, if you plan on purchasing another bird, both should be screened for polyoma virus, as either or both birds can be carriers without showing signs.

How is polyoma virus treated?

There is no definitive treatment for birds with polyoma virus infection other than supportive care.

Can I prevent polyoma virus infection?

Manual removal of droppings and feathers followed by careful disinfecting of the environment can help reduce viral contamination of the environment. The DNA probe test should be done on currently owned birds and new birds before they are put together. Because birds can shed the virus intermittently, several negative tests are needed to be somewhat certain that a bird is not a carrier. A polyoma virus vaccine is being developed that may prove effective. However, a basic precaution is never to rear budgerigars in the same airspace as other parrots.