If they cannae eradicate germs in hospitals then how can you expect to eradicate them in a pigeon loft, you have to manage them simple as that. If you go on holiday or in fanciers terms send your birds to race you take precautions.
I have travelled quite a bit and if I go to a place like XXXXX where typhoid is rife I get a vaccination to boost my immune system before I go, it does not stop me from getting it but it is the best available safeguard apart from not going in the first place. But I do know guys that go to work in these places that do not take the precausions and think it will never happen to them, I am sure it is the same in all walks of life including pigeons :-/