This is taken from the DEFRA site: https://secure.fera.defra.gov.uk/beebase/index.cfm?pageid=89
European Foul Brood (EFB)
EFB is caused by the bacterium Melissococcus plutonius. Larvae become infected by consuming contaminated food fed by the nurse bees. The bacteria multiply within the larval gut, competing with it for its food. They remain in the gut and do not invade larval tissue; larvae that die from the disease do so because they have been starved of food. This noramlly occurs shortly before the cells are capped.
For more information please see the Foulbrood Disease of Honey Bees advisory leaflet and the OIE Chapter on EFB.
Symptoms of EFB
An infected colony may show some or all of the signs below:
Erratic or uneven brood pattern
Twisted larvae with creamy-white guts visible through the body wall
Melted down, yellowy white larvae
An unpleasant sour odour
Loosely-attached brown scales
Unlike AFB, the remains of larvae that die from EFB do not rope when drawn out with a matchstick.
As with AFB the beekeeper is the primary method of transmission, if brood combs other items are transferred from an infected hive to a healthy hive. However, robbing of weakened infected colonies and swarms are also methods by which the disease can be transmitted.
Ther are three options available to the beekeeper in the UK who has colonies infected with EFB;
The colonies may be treated with the shook swarm husbandry method. In trials conducted by the National Bee Unit showed that Shook swarm is more successful than OTC for the control of EFB in England and Wales. In the Spring following treatment, shaken colonies were three times less likely to test positive for M. plutonius. This finding appears logical since OTC treatment does not remove the etiological agent present in the hive. In contrast, the Shook swarm method provides the bees with M. plutonius-free material. In addition, OTC treated colonies were five times more likely to show recurrence of EFB the following year than Shook swarm treated colonies. A full copy of the project report is also available.
The colonies may be treated with the antibiotic oxytetracycline (OTC, as the formulation Terramycin®).
The colonies may be destroyed, as for AFB. This will be carried out if the colony is too small for other treatment methods, is too heavily infected to respond to treatment, or at the beekeepers request.
However, the range of options available will also depend upon the time of year that the disease is diagnosed and other factors such as the strength of the colony or the level of infection. Should EFB be diagnosed in your bees, these options will be fully explained to you by your local Appointed Bee Inspector (ABI) to allow the best course of action to be taken.