Yes, I was keen to find out what was happening in that one so - despite the cool afternoon (about 13C) - I shook the bees into the box from all the frames with brood. It was packed with bees and they were none too pleased.

Beekeepers really should have an inspection specifically to look for brood disease and this is the ideal time to do it as EFB is more likely to be showing itself. Take out a couple of non-brood frames, clear a space, and give the frame a sharp tug while held in the space.

Look for AFB (and also EFB) under cappings that are a little different. Darker, ruckled, perforated? Knock the capping off. Look for EFB (and also AFB!) in open brood, even small larvae can be affected. Twisted or melted down larvae indicate EFB.