>As with any natural system, effects vary considerably.
>It is well documented that European honeybees, with the ability to detect and
>remove diseased brood, can be completely AFB resistant (Spivak and Gilliam
>1998).

While it has been demonstrated that some hives of bees are not overcome by AFB
under controlled and supervised conditions and also observed in the field where
inspectors have come upon entire apiaries overcome by serious AFb, yet found a
colony or two among them unaffected and happily robbing the others, let me caution
that in the real world, no beekeeper can be certain to maintain 100% resistant stock.

Even where superior and proven stock is chosen, hives requeen themselves (and
who knows what drones may be involved?)  

Moreover, the resistance is not reliably heritable.  There are liable to be a few outbreaks
even when resistant stock is employed.  Any such outbreak, unless dealt with
immediately will, over time, greatly increase the challenge to other nearby hives.

Reportedly, some bees, if kept reasonably pure and isolated are able to stand up to
AFB.  The Primorsky stock is,  I have been told in conversation with Tom and Charlie,
one of them.

Nonetheless, most of us either cannot or will not do what is necessary to maintain
such stock and deal with exceptions.

My own experiments with bad beekeeping now that I am retired and can just play
with things I would never have dared try when my living depended on it have shown
me clearly that relying on assumed resistance without vigilance and the will to take
drastic and immediate action can result quickly problems which avalanche rapidly.

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