American foulbrood (AFB) is the most contagious, serious bacterial disease of honeybee brood caused by the bacterium Paenibacillus, which is a virulent spore-forming organism. This disease can appear and spread quickly throughout a colony.  The spores are the infective stage of the disease – infection begins when food contaminated with spores are fed to larvae by the nurse bees. Once in the gut of the larva the spores will germinate; the bacteria then moves into the larval tissues, where they multiply enormously. Infected larvae normally die after the cell is sealed and millions of infective spores form in the larval remains. As these spores remain viable for many years and are very resistant to extremes of hot and cold and to many disinfectants in the UK, the only current treatment is destruction by burning the hive.