After spending a lot of time researching and talking to my local vet. I have found a medicine called Interferon. It is an injection that is given to PBFD birds three times a week for 16 weeks. It has been tested on birds with full blown PBFD (showing feather symptoms) and on birds who clinically have the virus but are not showing any symptoms.
The results of the studies showed that the Interferon had no effect on the birds with feather symptoms showing, although for the other birds that recieved the treatment with no feather symptoms, they made a full recovery and many of them had no symptoms and a happy, healthy life.
So for those people who have had their birds tested and they got a positive result, if the bird/s are not showing any symptoms it may be worth talking to your vet about Interferon. It is not cheap and semi-difficult to get a hold of, but I could never put a price on my little Ollie, anything is worth a try.
http://www.healthandhygiene.co.za/document_uploads/rhh90b(1).pdf
