ASK THE VET (Polyoma virus and psittacosis)

This article first appeared in SQUAWK, the newsletter of the Big Apple Bird Association and is reprinted with permission.

I would like to address two comments that appeared in a September 18, 1995 letter Terri Leinneweber. It was stated that a Caique died as a result of polyoma virus "which was spread genetically from diseased parents" and that a replacement bird would be provided from the breeder. Avian polyomavirus is known to infect a wide range of psittacines and passerines. The virus is known to cause severe illness and death in many different species of birds. Infections in young birds are often rapidly fatal. Depression, loss of appetite, delayed crop emptying, regurgitation, diarrhea and hemorrhage under the skin may occur prior to death. A chronic, progressive form of the disease also exists. Many budgies may be subclinically infected with polyoma virus and shed the virus when stressed, such as during breeding. The virus is not spread genetically. It is believed to be spread horizontally through feces, feather dust, respiratory secretions, crop secretions and urates in the droppings . Vertical transmission is also known to occur through the egg in the budgie. It is not known if transovarian spread occurs in other species. A bird of the same species acquired from a breeder who has polyoma in her birds may also be infected, even if not showing clinical signs of disease.

The second comment is in reference to a cockatiel positive for psittacosis, that was isolated and is now cured. Psittacosis is a bacterial infection caused by Chlamidia psittaci. It is able to infect birds, humans and other mammals. The organism is shed in nasal and ocular secretions, feces and feather dust. Birds become infected when they inhale or ingest infectious particles.

Diagnosis can be very difficult. Some infected birds may appear ill, while others are latently infected and can act as carriers of the infection to other birds.

If one bird is diagnosed with psittacosis in a collection or store, certain measures must be taken to prevent the spread of disease. The organism can remain infectious in dried secretions, excretions and feather dust for very long periods of time. Good disinfection -- using an agent such as Roccal -- and proper hygiene are essential. All birds in the group should be quarantined and observed for a 30 day period and tested or prophylactically treated with tetracycline orally, in the food, or by injection for a 45 day period. Psittacosis is transmissable to people. Very young, very old or immunocompromised are at highest risk.