I have lost two out of 31 as of last week.  Both were very strong in early Oct.  When I opened them there simply were hardly any dead bees anyplace including on the bottom board.  I do not remember ever opening a dead hive to find so few bees left in it.  Both had over 75 pounds of honey left.  No sign of any dead brood.  I treated once last summer with apivar strips that went on about March 15.  My Sept. counts were running zero to two mites per 100 bees by an alcohol wash.  Our NE Ohio winter has had pretty normal temps over all, but we have not had any sudden cold snaps below zero like we so often get.  I presume the two losses were virus related and sick bees flew away from the hive.
Dick

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