Avian Polyomavirus (APV), also known as budgerigar fledgling disease, is a viral infection that affects parrots and other bird species. Infected birds may show clinical signs such as feather abnormalities, delayed feather development, lethargy, loss of appetite, skin haemorrhages, and pallor. The virus is primarily transmitted through feather dander and droppings.

APV is a major concern for bird breeders and keepers, as it can cause sudden death in chicks and nestlings, which are the most susceptible. While adult birds often survive infection, they may become asymptomatic carriers, shedding the virus intermittently. Furthermore, co-infections with Beak and Feather Disease Virus (BFDV) can exacerbate APV symptoms, leading to more severe disease progression.

Testing for APV can be done via  a blood sample or a cloacal swab.  From a single blood sample we can test for APV, BFDV, and Sex.