> > I am looking for a little more science behind a dormant period of
> [AFB]spores and what type of environment can activate them. Is it mostly
> conjecture on how ones hives can get this brood disease? Does anyone know
> for sure how their hives got this?
>

Deb, the spores remain viable essentially indefinitely.  What I see is that
if a highly-hygienic colony cleans up diseased larvae to the point of being
undetectable, the disease may recur when the colony gets nutritionally
stressed.

Contrary to popular belief, it takes a lot of spores to start the disease
in a hive.  Colonies used to be regularly exposed to AFB spores, yet seldom
came down with disease.  Yet once one finds a single diseased larva, one
should just go ahead and burn--some years ago I tracked colonies with a
single diseased larva to see whether the disease would disappear.  It
didn't.

A number of experts who have studied AFB extensively have told me that it
is mostly a beekeeper-caused disease, via the swapping of combs.

Many commercial beekeepers in the US have confirmed my observation that AFB
is now much rarer than it used to be.  I'm not sure whether this is due to
the widespread use of Tylan, or to bees becoming more resistant, or
something else.

I used to see a good deal of AFB in my operation until I instituted a zero
tolerance policy involving burning infected frames and sterilization of
boxes.  And zero input of bees or equipment from other operations.  Over
the past several years (with no propyllactic antibiotic treatment) we find
fewer than three infected hives out of 1500 each season.

But there are areas in Northern California full of hobby beekeepers, in
which AFB is flaring up and spreading.

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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