In any case, the use of a banned nosema drug to illegally treat AFB in the US is not a widespread practice and in all likelihood is not happening at all.
Secondly, vast numbers of drug fed AFB infested beehives from Canada are not being shipped to the US to pollinate almonds.
And, what laws and practices that apply in Canada do not necessarily apply in the US. Far as supposed drugged bees go, they don't.
But mostly, it's all moot anyway in relation to the use of an AFB vaccine in New Zealand. What some people claim Americans might or might or might not be doing, or what Canadians might or might not be doing, is just a red herring far as our own use of an AFB vaccine goes, here in New Zealand.