Dee I think it was technique - 300 bees in a jar roll them and count the mites - I think it was a cruel waste of bees - I think using an icing sugar sprinkler on the bees on the frames would have been a better way.
All of my bees have been broodless for various reasons over the Summer, so that helps and the vape.
@TreeCamper my Sapphire had a nosema problem beginning of April - and I had several bees with DWV. even though there were very little if any Varroa going into Autumn.
There is a recent article I read said the Queens can pick up DWV and other viruses from mating - they have collected phallus’ from returning Queens newly mated returning back from the DCA (Drone Congregation Areas) and have found signs of Virus from the Drones that can infect the Queens - the Queens who were previously from disease free hives were showing signs of virus back at the hive emanating and spreading from the ovaries.