What is Polyomavirus (Non-budgerigar Psittacine)?

Avian polyomavirus is a virus that often leads to severe disease and sudden death in many types of psittacine and non-psittacine birds. Currently an agent of infectious disease in birds worldwide, avian polyomavirus is primarily causing damage to the health of budgerigars (budgies), macaws, conures, eclectus parrots, ringneck parrots and lovebirds. At present time, the avian polyomavirus is the leading cause of death in young, unvaccinated parrots. The virus is leading to a life-threatening disease in birds called French molt or “feather losing disease.” Since the virus is highly contagious, it can spread quickly throughout entire aviaries.

French molt takes its greatest toll on neonates or very young chicks, likely due to their underdeveloped or emerging immune systems. Once the young psittacine becomes ill with French molt, the bird will quickly lose most of its larger feathers, as well as the ability to fly for the rest of its lifetime. The bird will also sustain damage to an already fledgling immune system, which increases its vulnerability to bacterial or viral illness. In this case, to protect the aviary some may choose to cull the bird, even if there is a regrowth of feathers. In many cases, however, the bird will experience sudden death without revealing any signs or symptoms of illness. Even when born appearing fully healthy, an infected chick will suddenly “drop” its largest feathers, show signs of lethargy and stop eating. Within 24-48 hours, these birds will usually succumb to death. Mortality rates in birds less than two weeks of age are as high as 100%. In addition to chicks, adult psittacine birds also become infected. In most cases, adult birds survive infection, though subtle symptoms such as appetite loss and diarrhea may occur. 

Currently, any member of the Psittacidae bird family, such as parrots and cockatoos, is highly susceptible to avian polyomavirus. An enormous range of bird families are also at risk, including Passeriformes (weaver finches, canaries), Galliformes (chickens and turkeys) and Falconiformes (falcons and hawks). While the virus was identified back in the 1980’s, the mechanics, causes and treatment possibilities of the virus, and any resulting diseases, continues to confound avian veterinarians, researchers and breeders. Research is currently happening worldwide in hope of preventing a potential outbreak of APV infection in the future. In the meantime, to prevent the spread of infection within your aviary, it is imperative to vaccinate the adults.

Avian polyomavirus is a highly contagious virus that may cause serious disease or death in birds, particularly in budgerigars (commonly called budgies or parakeets) and psittacines (parrots).

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Symptoms of Polyomavirus (Non-budgerigar Psittacine) in Birds

  • Loss of appetite
  • Depression
  • Lethargy
  • Weight loss
  • Vomiting
  • Diarrhea
  • Bleeding under the skin

Causes of Polyomavirus (Non-budgerigar Psittacine) in Birds

Polyomavirus infections “ignite” upon different forms of stress, including poor nutrition while breeding, over-breeding, mites and insects. Transmission of the virus occurs either directly from bird to bird (parental feeding), or may be attributable to environmental conditions, including a lack of hygiene in the aviary. Feather dust and bird droppings may be culprits, particularly the ingestion or respiration of contaminated waste in food and water. One form of transmission occurs per infected respiratory droplets that circulate through air systems in unsanitary aviaries.

The introduction of a new bird is always a risk; buying and selling and appearances at shows must be taken very seriously due to the highly contagious nature of French molt. The virus is also transmissible between aviaries when contaminated goods are exchanged. Specific quarantine procedures must be followed. Egg transmission has been documented in budgerigars, but not in psittacines.

Diagnosis of Polyomavirus (Non-budgerigar Psittacine) in Birds

Post-mortem, the virus is diagnosed based, in part, on the appearance of enlarged hearts and livers. Tissues, the brain and various organs are examined for viral spores. 

In surviving birds, the diagnosis can typically be made by physical exam, DNA probe, fecal exam and a blood sample. An antibody assay can be used to detect previous infection. 

The primary observable characteristic of the virus is the loss of feathers. Otherwise, diagnosis of a live bird is challenging since clinical symptoms mirror other infectious illnesses. 

If a bird dies, immediately take care to wrap the body and place in a refrigeration unit. Bring the bird to your veterinarian for necropsy so the presence of the virus can be determined.

Treatment of Polyomavirus (Non-budgerigar Psittacine) in Birds

There is no specific treatment for avian polyomavirus in psittacines; therapy is typically supportive in nature. Strategies for quarantine, as well as the potential benefit of nutritional supplements, should be discussed with a veterinarian. Some vets choose to treat affected birds with antiviral medications such as acyclovir or AZT, as well as injections of vitamin K.

New birds and visitors should not be allowed in the aviary or nursery. Complete isolation means that the bird must be protected from any direct or indirect exposure to other birds. Many bird fanciers are surprised to learn that the virus may be introduced into an aviary or nursery upon shipment or attainments of goods from a warehouse or store that keeps live birds for sale or observation.

Recovery of Polyomavirus (Non-budgerigar Psittacine) in Birds

Affected birds can be given special nutritional supplements and silica, per veterinary advice. 

Prevention is your best course of action. It is imperative for the health of your aviary or bird to keep the living environment disinfected. Polyomavirus appears to be resistant to most grocery-store type disinfectants. Ask your veterinarian for a recommendation of a safe, commercial-grade disinfectant. 

Insect activity must be controlled immediately. Thoroughly clean all utensils, wear gloves, and wash your hands between handlings. 

In the meantime, to prevent the spread of infection within your aviary, it is imperative to vaccinate the adults. Please follow up with your veterinarian about this vaccine, as well as a yearly booster.