> Nosema needs a live host I believe.
Nosema makes spores. Not as long lived as AFB (totally different genus and species...) but they can live a while. The latest research seems to be that Nosema apis has virtually disappeared and that is the one that causes dysentery, and it has been replaced by Nosema cerana, which does not cause dysentery.
If it is Nosema apis, yes, the queen can (and often does) get it and it seriously affects her ability to perform.
Generally, though, feeding will clear up Nosema apis. Just moving something through their digestive system flushes it out.