Polyoma Virus Infection in Birds

By Rick Axelson, DVM

General Information

The polyomavirus of pet birds belongs to the family Papovavirus, the same group of viruses that causes benign skin tumors (papillomas or warts) in birds. Polyomavirus can cause benign feather lesions in budgies (the so-called French molt or Budgerigar Fledgling disease) or acute death. Species particularly susceptible to polyomavirus infection include budgies and members of the parrot family; to a lesser degree, canaries and finches are also susceptible.

How do birds get a polyomavirus 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 (produced for feeding their offspring). It is unknown how long it takes from the time of infection until death (if it occurs); however, death may occur anywhere from 2-15 days after birth (e.g. budgerigars) to 140 days (e.g. larger parrots).

What are the signs of polyomavirus infection?

There are different strains of the virus that can cause different clinical signs. Some birds recover from the infection but are left with abnormal feathers (Budgerigar French Molt). Most commonly, birds die quickly with no clinical signs. Some infected birds may show depression, anorexia, weight loss, delayed crop emptying, regurgitation, diarrhea, wet droppings, dehydration, difficulty breathing, abdominal enlargement, hemorrhagic areas under the skin, and tremors for 12-48 hours before death. Mortality 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.

"Mortality can be high, reaching 100% in birds less than 15 days old."

polyoma_virus_infection-1How can I tell if my bird is infected?

Birds, especially baby birds, die quickly; if you have a baby bird that dies suddenly, it should be examined by a veterinarian. Both sick and healthy birds can be tested using a specific DNA probe of a cloacal swab, easily obtained by the veterinarian.

My bird is healthy. Should it be tested?

This can best be decided by your veterinarian. However, if you plan to purchase another bird, both should be screened for polyomavirus, as either or both birds can be carriers without showing signs.

How is polyomavirus treated?

There is no definitive treatment for birds with polyomavirus infection, other than supportive care. Birds with mild hemorrhaging might benefit from vitamin K injections and supportive veterinary care. Often, the disease progresses so quickly that no treatment will be effective.

Can I prevent polyomavirus 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 newly acquired 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 polyomavirus vaccine is available for selected psittacine birds (parrots) as an aid in the prevention of avian polyomavirus.

"Vaccine is available for selected psittacine birds (parrots) as an aid in the prevention of avian polyomavirus."

It is extremely important that you discuss this disease with a veterinarian familiar with birds.

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