bird on hand

Avian Polyoma Virus and Awareness

The Avian Polyoma Virus has been associated with devastating disease outbreaks in companion birds in North America, Europe, Africa, and Australia for more than 15 years.  It affects psittacine birds as well as passerine birds such as finches and canaries.   Disease Caused by the virus has manifested itself in a variety of forms including budgerigar fledgling disease (often producing acute mortalities), French Moult (abnormal feather development in budgerigars) and acute mortalities in young psittacines.  Polyomavirus infection and disease signs more commonly occur in young birds, but a significant number of mortalities involving older birds have been reported, particularly Eclectus parrots, Cockatoos, Lovebirds, and Caiques.  The Virus is the type that is shed intermittently.  In other words, a bird with the virus does not constantly pass it.  It is therefore more challenging to detect.

Clinical Signs

Many young birds infected with the virus die suddenly with no outward signs of disease.  Others can become lethargic, the crop slows, they may also show signs of bruising under the skin and die within 12-48 hours.  Severe liver damage is observed at necropsy.
Psittacines are considered highly susceptible to polyomavirus infection.  The infection can occur in either parent raised or hand raised babies and signs are most frequently observed in infected birds at weaning.  Younger and older birds can also die from the infection.  Mortalities in an aviary can vary from 25-100% of the at risk young birds.


  • Polyomavirus can be transmitted in a variety of ways:
  • Direct contact with contaminated feces.
  • Feather dust
  • Secretions from the lungs or crops from infected birds


  • Serology-Done with a blood sample.  A positive test means that the bird came into contact with the virus some time but may not be shedding the virus at this time.  A negative test can still mean that the bird is shedding the virus so this test is not very useful in a clinical situation.
  • DNA Probe- This test is much more helpful in a clinical situation.  A sterile swab of the cloaca positive test indicates that the bird is actively shedding the virus. A negative test indicates that the bird is not shedding the virus at the time the test was taken but still may be carrying the virus.  A bird that is stressed, i.e. moving to a new home will usually shed the virus.
  • Histology-After the death of a bird a necropsy can be done.  Tissue samples are taken and sent to a lab where they can detect polyoma virus.  If a bird dies of unknown causes, wrap it in a bag and place in the refrigerator.  Notify your veterinarian as soon as possible.


Good hygiene and sanitation practices combined with a balanced diet may help limit risk.  It is important to follow these basic guidelines:

  • Use a closed aviary approach.  This means that no baby enters the nursery that has not come from your closed aviary.
  • If this is not possible don’t mix babies from different sources in the same air space.
  • Quarantine new birds for a minimum of 60-90 days.
  • Do not allow visitors into the nursery.
  • Use separate feeding utensils for each bird.  Disinfect thoroughly after use.
  • Control insects.  They can carry the virus from one bird to another.
  • Wear gloves and disinfect hands before handling birds.
  • Keep unvaccinated birds away from unvaccinated psittacines.  Especially lovebirds, cockatiels, and parakeets.
  • Vaccinate


The following guidelines for vaccination are recommended to help prevent polyomavirus.

  • Vaccinate adult birds during their non-breeding season
  • Vaccinate chicks at 40-50 days and booster at least one month before shipping.
  • After initial vaccine a booster is given in 2 weeks.  After that a yearly booster is required.