Other hive parts an unknown factor ...
The importance of other hive parts (e.g., empty supers, floor boards, hive mats, division boards, and lids) in the spread of AFB is unknown. However, they are likely to carry fewer spores than either frames of brood or wet honey frames, and so are probably less important in the spread of AFB.
... with one exception
The one exception may be floorboards. As bees remove diseased material, pieces are often dropped on the floorboard. It is therefore good practice to thoroughly scrape the hive detritus off all floorboards before placing them under a new hive.
Scrape the detritus off floorboards before placing them under a new hive.