POLYOMA VIRUS INFECTION
General information
The polyoma virus of pet birds belongs to the family Papova virus, the same
group of viruses that causes benign skin tumors (warts) in birds. Polyoma virus
can cause benign feather lesions in birds (the so-called French molt) or sudden
death.
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 (e.g. 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 recover from the infection but are left with abnormal feathers
(French Molt). Other birds die quickly with no clinical signs. Still others
may show abdominal enlargement, hemorrhage areas under the skin, and tremors.
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.
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. Birds with mild hemorrhaging might benefit from vitamin
K injections. Often, the disease progresses so quickly that no treatment will
be effective.
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.
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