A condition of bees, not a disease
Dysentery can be caused by the build up of material in the bodies of bees. If they are unable to take cleansing flights, such as during the winter when they are confined, they defecate within the hive. This shows as a large number of spots on the frames and combs. In extreme cases there is spotting on the front of the hive. Food of a high water content will cause this, so will fermented stores.
Soiling is cleaned up by house bees and if the colony is suffering from nosema the infection is quickly spread.
It is often assumed that a colony that is suffering from dysentery has a bad case of nosema, but this may not be the case.