what is polyoma?

[sweetie&meli]

Hey everyone , i know i work in a petstore and should know this but lol i dont so i turn to you , my baby boy kitt was vaccinated for polyoma ..what is this and why are all our african parrots vaccinated and not the other ones , is there ertain things that african parrots are supseptable to that others arent?

[Graehstone]

Hope this helps a bit to 'splain things ...


ASK THE VET (Part I: Avian Polyoma)
by Linda Pesek, DVM
Westbury Animal Hospital
319 Union Avenue
Westbury, NY
516-333-1123

All newly acquired birds, especially those to be used for breeding, should be screened for avian polyoma virus.

Avian polyoma virus causes high levels of mortality in young psittacine birds. It is thought that several strains of polyoma virus exist, with certain strains affecting one species and not others. Species differences in susceptibility to infection may also exist, since polyoma virus appears more prevalent in macaws, conures, Eclectus parrots, lovebirds, cockatiels and budgies than in other species.

Budgerigar Fledgling Disease (BFD) was the first identified acute generalized infection associated with avian polyoma virus. Clinical disease appears to depend upon the age and condition of the bird when exposed to the virus. In an infected flock, neonates can appear normal for the first ten to fifteen days and then die suddenly with full crops, while other hatchlings may develop swollen abdomens, discoloration of the skin, subcutaneous hemorrhages, head and neck tremors, ataxia and decreased down and contour feathers. Those infected budgies that survive may have symmetrical feather abnormalities such as dystrophic primary and tail feathers, and no down feathers on the back and abdomen. Primary and secondary feathers may fall out. These birds are often unable to fly. It is important to note that similar feather abnormalities may be seen with Psitticine Beak and Feather Disease (PBFD), but PBFD progresses, while feather abnormalities due to polyoma may resolve after several molts.

Larger psitticines may die suddenly without signs of illness, or die after showing depression, anorexia, weight loss, delayed crop emptying, regurgitating, diarrhea, dehydration, subcutaneous hemorrhages, dyspnea, ataxia and paralysis. Clinical signs are common at weaning and infected fledglings often die 12 - 48 hours after the development of clinical signs.

Both recovered budgies and larger psitticines are thought to remain infected, and serve as asymptomatic carriers.

A chronic form of polyoma virus is also thought to exist which causes weight loss, intermittent anorexia, polyuria, recurrent bacterial and fungal infections, and poor feathering.
Transmission:
Polyma virus is thought to spread both horizontally (bird to bird) and vertically (via the egg). Parents may transmit the virus to their offspring when feeding by regurgitation of exfoliated crop epithelial cells. The virus can replicate in feather follicles and thus be shed in feather dust (like PBFD). The virus may also be shed in the urine. Susceptible hosts may be infected by inhalation or oral ingestion. Although young birds are most susceptible, adult birds may also develop disease. The exact incubation period is unknown but may be anywhere from 1 to 2 weeks. Affected budgie fledglings show peak mortality rates between 15 - 19 days of life, while larger parrots may show signs between 20 - 56 days of age.

Some asymptomatic adults produce persistently infected young, while others produce some normal neonates. Asymptomatic adults who intermittently shed virus are thought to be responsible for the persistence, transmission and spread of the virus. Next month: Diagnosis, control and what to do with a positive bird.


(Avian Polyoma Virus/Part II)


Species differences in susceptibility to polyoma virus are thought to exist. Macaws, conures, Eclectus, African greys and Amazons are thought to be very susceptible to infection.

Polyoma virus can be present in a carrier state, with adult birds appearing clinically normal until they undergo stress. One type of stress that can cause a latently infected bird to shed virus is breeding. Increases in reproductive hormones -- estrogen, progesterone, and testosterone -- are thought to have an effect on the immune system and may be responsible for the activation, multiplication and shedding of the virus.
Detection of polyoma virus:
Postmortem detection of polyoma is based upon finding viral intranuclear inclusion bodies in the liver, kidney, spleen, heart and feather follicles. Identification of the virus in a live bird can be very difficult. Early tests looked for the presence of antibodies or proteins produced by the body against the virus. These antibodies, however, may no longer be present in a bird that remains infected by the virus. No correlation exists between serum neutralizing antibodies and viral shedding. This means that a bird could have a negative antibody titer and still shed the virus, or a positive antibody titer and not shed virus.

A new test, a DNA PCR probe test has been developed by Avian Research Associates. This test is able to detect polyoma virus in live birds that are shedding virus by analyzing cloacal swabs. The limitation of this test, however, is that a cloacal swab identifies only a bird who is shedding the virus at the time of sampling. A latently infected bird may not be shedding virus. Thus, a positive test indicates viral nucleic acid was found in the sample and confirms viral shedding, while a negative test indicates that the individual was not shedding virus at the time the sample was taken. It does not necessarily indicate the bird is free of the virus.

Since polyoma is a very infectious virus causing high mortality and morbidity in young birds, closed breeding aviaries are recommended. A cloacal swab should be checked on all birds leaving an aviary and all newly acquired birds before being introduced into a collection. Once the virus is introduced into a collection it is almost impossible to eliminate. This is because of carrier states that exist and because the virus is very resistant to many disinfectants.

Because a high incidence of polyoma exists in budgies and cockatiels, it is recommended by some that these birds not be kept on the same premises where other species are housed and bred.

Work is currently being done to try to produce a vaccination to protect against polyoma. Although results look promising, no vaccination is yet available. A bird positive for polyoma may be kept as a pet as long as it is in a single bird household. It should never come in contact with neonates (young birds) or birds to be used for breeding.

[sweetie&meli]

thank you soo much i dont feel stupid anymore:)