Psittacine Beak and Feather Disease (PBFD). In Australia, and probably other countries, PBFD and French Moult in budgerigars are the same disease.
It is an infectious virus. This was confirmed by studies undertaken by Dr David Pass et al from 1984 to 1987 but this is not a new disease – it has been around for several decades (at least).
Many species of Australasian psittacine birds and several species of African and South American psittacines are known to be susceptible and there is no reason to believe that all species aren’t susceptible.
Incidence in Captive and Wild Populations:
The disease is common in captive cockatoos of the genus Cacatua including the sulphur-crested cockatoo, galah, pink cockatoo, little corella, long-billed corella, lesser sulphur-crested cockatoo, triton cockatoo, and Goffin’s cockatoo. PBFD occurs uncommonly in the cockatiel and has been diagnosed in the gang-gang cockatoo. The disease is also extremely common in aviary collections of budgerigars and lovebirds.
PBFD occurs in wild psittacine birds in Australia. A prevalence of 10-20% has been reported in sulphur-crested cockatoos in South-Eastern Australia. PBFD also occurs in wild galahs and little corellas, rainbow lorikeets, king parrots, 28 parrots and red-capped parrots.
This disease also limits the success of breeding of the endangered species in captivity such as the orange-bellied parrot. A breeding program in Tasmania has been very successful but now that PBFD has appeared in the captive birds they won’t be returned to the wild as originally intended for fear of wiping out what is left of the wild population.
It is probable that natural infection is by the oral route but carriage of the virus on the eggshell is a distinct possibility. In aviaries the incidence of disease increases as the breeding season progresses and the same nests are used for successive clutches of eggs – this appears to be because the amount of virus, which is shed in faeces and feather dander, builds up in the nest. The younger a bird is when it is exposed to the virus, the greater the chance that it will develop the disease and the more severe the disease is likely to be. As birds get older they become more resistant. Species in the genus Cacatua are more likely to develop severe disease than other genera of psittacine birds.
What the Virus Does:
a. The virus causes death of the epidermal cells of the feathers and beak which upsets the normal pattern of growth of these structures.
b. The virus causes reduced function of the immune system.
Cockatoos commonly have severe feather loss, beak rot and suffer from impaired immunity such that they are likely to contract other infections. The smaller parrots rarely have beak involvement, commonly may only lose flight feathers and don’t seem to be affected by immunosuppression. Mildly affected parrots may recover clinically but they still could be a source of virus for other birds.
The prognosis for recovery of feather growth is poor. Some birds live for long periods with poor feathering, whereas others suddenly or progressively lose their appetite, become depressed, lose weight and die. In some cases degeneration of the beak impairs eating and leads to starvation.
There is no treatment or vaccine available for the control of PBFD. The current recommendation to vets is that infected birds be destroyed but in the case of pet birds this can be avoided until the bird begins to experience obvious pain and discomfort. In aviaries some control is achieved by strict attention to hygiene (cleaning and disinfecting nests between clutches) and culling affected birds. When purchasing a bird pay particular attention to the plumage and have any feather abnormalities, such as a dirty or greasy appearance, examined by a veterinarian to obtain an accurate diagnosis.