VN June 2023

Vetnuus | June 2023 38 • More common in juveniles than adults, but naïve adults are susceptible. Incubation • Minimum of 21-25 days, but it could be as long as several years. Transmission • The virus is shed in faeces, crop secretions and feather dust • Vertical transmission is suspected but not confirmed. Diagnosis • Histopathology o Basophilic intracytoplasmic inclusion bodies found in feather follicles and the cloacal bursa are considered diagnostic. Care must be taken not to confuse them with polyomavirus, herpesvirus or adenovirus. • Feathers and skin o Multifocal necrosis of epidermal cells, epidermal hyperplasia and epidermal hyperkeratosis o Diffuse necrosis of epidermal cells throughout the epidermal collar and inbasal and intermediate layers of developing feathers • Beak o Hyperkeratosis and separation of the cornified outer layer fromunderlying tissues and bones • Thymus and bursa o Atrophy and focal aggregation of necrotic cells • Serology o HI is a sensitive method for measuring antibody responses to PBFD. When combined with HA, it can give a review of the bird’s PBFD status. o Viral-specific PCR probes are themost sensitive test but give no indication of whether the bird is infected or transiently viraemic. Treatment • Avian Interferon may be of value if given before the bird shows clinical signs. • Otherwise, supportive care, e.g. treating secondary infections and providing a good diet, is all that can be done at this time. Prognosis • Some birds, e.g. lorikeets, may be able to mount an effective immune response and apparently recover. These birds probably become inapparent carriers. • Despite showing clinical signs, somebirdsmay live for 10 – 30 years o However, most infected birds die within two years of secondary diseases related to immunosuppression v This article is sponsored by V-Tech Technical I Article