>>We know that it only takes 3 - 4 spores if they are fed to a single larva at the right time to get AFB symptoms. <...> 1 dead larva makes about 2 -3 billion spores.

I've always wondered if AFB can reproduce (and increase the spore count) without manifesting the clinical signs (dead larvae).  I believe AFB develops in the bee gut so I'd think, if any new spores are produced, they'd be removed on the first cleansing flight.  Anybody know for sure?

Someone once pointed out somewhat flat/sunken cell cappings in one of my weaker hives.  There wasn't the characteristic AFB smell.  Decapping the cells revealed nice, healthy, white larvae.  Can there be a 'partial AFB infection' without the full clinical symptoms?

>>Every year a lot of spores go out of the hive with extracted honey, bee excrements etc.

I've heard from a couple of older beekeepers that the soil in an apiary can be 'contaminated' with AFB spores and moving the apiary is the only way to prevent re-occurrence.  But perhaps this only puts distance between the apiary and AFB hives in the area.  The soil spores may not get carried into the hives.

Waldemar

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