Yeah, I agree with Sailboat, you got absolutely NO information that you needed to know, not even the basic stuff. You'll be all the much better for simply doing as much research as you can on PBFD yourself.
As far as transmission, from what I can remember from my days working in the Animal Diagnostic Lab at Penn State, most birds acquire PBFD as hatchlings from their parents or other infected birds in the aviary, but it can be acquired by adult birds through the feces, crop liquids, and from the pieces of feathers and their beak. It is a virus with no direct CURATIVE treatment as of now, but that doesn't at all mean that your bird cannot live a wonderfully full life, EVEN IF HE LOSES HIS FEATHERS! There are many cases of parrots with PBFD losing all of their feathers but besides that outward symptom they are fine...BUT MOST OF THOSE PARROTS ARE ON DIFFERENT MEDS/NATURAL SUPPLEMENTS, ALL OF WHICH SHOULD BE GEARED TOWARD PREVENTING A SECONDARY INFECTION FROM DEVELOPING!!!
And this is what your vet failed to even mention, which is upsetting to me...The key to a bird living with PBFD is preventing their deteriorated immune system from becoming prey to a secondary infection, meaning a Bacterial, Fungal, or even a different Viral infection, BECAUSE THIS IS WHAT TYPICALLY KILLS BIRDS WITH PBFD! Their immune systems are compromised, opening them up for easily contracted, secondary infections, simple infections that other birds would either fight-off naturally or be able to get rid of with medications like antibiotics. PBFD birds have a very, very tough time fighting-off illnesses, even simple bacterial infections, and this is what they typically die from.
I don't know how useful Interferon is for the treatment of PBFD, I honestly don't. The fact that your vet didn't even mention the risk to his life from secondary infections, and the things that you need to do to keep him from acquiring one, leaves me less than confident in him and his treatment plan...Instead, you need to either find a Certified Avian Vet who has experience treating birds with PBFD, as this current vet admitted he has not treated a single bird with it in his career (by the way, that fact does not at all mean that he got PBFD from the shop or the breeder, don't assume that)...
The 2 things that I would do right now are #1) Start calling around and find yourself the closest Certified Avian Vet with experience treating parrots with PBFD, so that they can get your bird's records sent to them, and you can get him to him ASAP for a consultation. Even if you have to drive him a few hours one-way it will be worth it, as they will be able to assess his overall-health and make specific, tailored recommendations that are going to help him and his case, and put him on whatever medications and supplements are going to help him. They will also teach you what you need to do as far as cleaning, contact with other birds/people with birds, food prep and disposal, etc. to ward-off secondary infections that may effect him...And then it's not a situation where you'll be driving him back and forth hours every week or month, this is going to be a marathon and not a sprint, so a good, experienced vet will get you and your bird all set-up during your first visit for his long-term care and your long-term behavior that will help his care and health...
#2) Get online and find other people with parrots that have PBFD, associations, organizations, etc. THESE ARE YOUR GREATEST RESOURCES! You'll find out what helps most, what helps some, what helps few, and what ALL OWNERS need to do. It will also provide you an invaluable support system of people who know what you and your bird are going through, and give you some positive outlook, as many birds lives for years and years with this disease and have an awesome quality of life once they are put on the correct meds and supplements...
