WHICH BIRDS ARE MOST AT RISK?
All species of parakeets and parrots are susceptible to the disease. However, lovebirds, parakeets and cockatiels are often affected by the disease without necessarily showing clinical signs. However, they are a significant source of contamination for other birds. In addition, younger birds are particularly susceptible to polyomavirus compared to adults.
TRANSMISSION
Although the mode of transmission of the disease has not yet been definitively established, it appears that the disease is most likely transmitted through inhalation of the virus (airborne transmission). Infected birds shed the virus into the environment through their feces, respiratory secretions, and feather dander for a period ranging from 4 to 16 weeks. In birds with compromised immune systems, this period may be significantly longer, or even continuous. Additionally, transmission by indirect contact—such as through objects or by humans who have been in contact with an infected animal—is also possible.
CLINICAL SIGNS
- Increased nest mortality;
- Distension in the abdomen (ascites, increase in liver volume, etc.)
- Various neurological signs
- Abnormal growth or absence of feathers, wings (remiges) and tail (rectrices) (especially in parakeets)
- Difficulty breathing (especially in young cockatoos)
- In adults, the infection is often asymptomatic (without symptoms)
PATHOGENESIS
Polyomavirus causes problems in several organs. It causes liver necrosis, kidney problems (immunogenic glomerulopathy), generalized hemorrhages, etc. Clinical signs of the disease usually appear 10 to 14 days after exposure to the virus. This period may however vary. Some birds are affected by the disease but do not develop clinical signs. However, they remain carriers of the virus for a certain period of time ranging from a few weeks to a few months. During this period, they continue to excrete the virus into the environment, potentially infecting other birds. Some birds are able to fight off the infection and eliminate the virus. Another disease, feather and beak disease, can promote polyomavirus infection by weakening the immune system.
DIAGNOSIS
It is possible to detect the disease even when the bird does not show clinical signs. To do this, a blood sample and swabs from the cloaca and choanae are taken at the hospital.
DISEASE PREVENTION AND CONTROL
Since there is no specific treatment for the disease, ideally any new bird should be tested for the disease, especially if several young birds are kept at home, or if the bird has potential contact with other birds, for example when boarding or visiting. It is also recommended to carry out screening tests if the origin of the bird is undetermined, doubtful or at risk. Disinfection of the environment is also essential. According to the latest data, this virus would be very resistant to many disinfectants and different environmental conditions.
Effective disinfectants would therefore be: Oxyfresh (1:400), bleach (1:10), 70% ethanol and Avinol-3 (synthetic phenol). A thorough cleaning should always be carried out before any disinfection. Ideally, food, toys and other materials should not come from an area where untested birds are present. There is a vaccine against polyomavirus. This one seems pretty effective. It is mainly used in breeding contexts or in large bird colonies.