I need to draw on your collective erudition!

In 2018 I had an EFB outbreak traced to a nearby neglected set of hives. I medicated my apiary, and did the medicate-shook swarm-medicate protocol on all symptomatic hives (8). Of the 8, 6 experienced a rebloom of the condition. Perhaps OTC resistance, perhaps they just kept robbing the infected apiary. I moved all my colonies and had no more EFB for the rest of the year (June onwards).

Suitably traumatized, I bagged all infected equipment for irradiation. Alas I had to store these outdoors, the field mice chewed into the bags and in January I caught the bees robbing the bagged equipment. I hoped that 6 months in the bags and multiple hard freezes had attenuated the bacteria, and I promptly removed all the bagged equipment to a bee-proof location.

In the spring all looked well. I was inspecting carefully, worried about reinfection. Multiple rounds of healthy brood later, there was a rebloom across the apiary, in 18 of the 20 overwintered colonies, in mid May. The worst were euthanized, but 13 are undergoing the medicate-shook swarm-medicate protocol, hoping to remediate the colonies.

So my question is: was the infection from the robbing of the bagged equipment in January? Could the symptoms delay that long from the robbing incident? Or does this sound like another case of infection from an outside source?

Many thanks all for your thoughts on this,
Janet

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