Contamination by flower spores
Bees picking up chalkbrood spores from flowers has been suggested as a means of spreading chalkbrood disease, a fungal disease infecting bee brood. However, unlike AFB spores, relatively few chalkbrood spores need to be carried back to a hive to create an infection.
Except where bee-collected pollen is applied to flowers in commercial quantities during artificial pollination, honey bees are very unlikely to pick up enough AFB spores from flowers to initiate the disease.
Contamination by infected soil
Many beekeepers have heard stories about a colony developing AFB after it has been placed in the same position in an apiary as a previously removed AFB hive. The new infection is usually blamed on the contamination of soil in front of the hive with AFB spores.
Research has shown, however, that soil is unlikely to be a source of AFB infection. One study looked for spores in the front of AFB infected hives, but was unable to find any at all. The study demonstrated that rain water quickly leached the spores from the soil surface.
Flowers and soil are not a factor in the spread of AFB.