Avian Harnesses Nylon Standard polyomavirus (APV) and psittacine beak and feather disease virus (PBFDV) induce contagious and persistent diseases that affect the beaks, feathers, and immune systems of companion birds.APV causes hepatitis, ascites, hydropericardium, depression, feather disorders, abdominal distension, and potentially death.PBFDV can induce progressive beak deformity, feather dystrophy, and plumage loss.We conducted the first prevalence survey of Massage Oils both APV and PBFDV infections in companion birds in eastern Turkey.