David Eyre wrote:
<I couldn't, and still don't understand what the genetics of the queen has
to do <with a spore disease. That's a bit like suggesting the re-queening of
a hive <suffering with foul brood, a waste of time.

Correct me if I'm wrong, but I believe the mechanism behind re-queening
isn't so much the genetics (though that could be a factor) as it is the
break in the brood cycle.  I understand that this allows the bees the
opportunity to clean up the brood comb prior to more eggs being laid.