The two bee diseases that beekeepers fear, namely American Foulbrood (AFB) and European Foulbrood (EFB), are notifiable diseases under the Bee Diseases and Pests Control Order 2006 (as amended), and suspected outbreaks must be reported to the Inspectorate who will then inspect and diagnose suspect colonies using Lateral Flow Devices (LFDs). If there is a positive diagnosis the apiary will be the subject of an immediate control (standstill) order whereby no hive products (honey or wax), bees, or hardware (hives, frames etc) may be moved out of the apiary.

If there’s a positive diagnosis of AFB then diseased colonies and hardware will be destroyed by burning in a deep pit, which is where Bee Disease Insurance (BDI) comes in handy. The same happens with serious cases of EFB, but in some instances EFB-infected colonies can be nurtured back to full health and, when re-tested, will have a negative diagnosis and apiary management can return to normal. It can, though, take many weeks for an infected colony to recover.

American Foulbrood

As you can see, the very worst thing that can happen to our bees is that they contract American Foulbrood (AFB). This disease didn’t come from America, but was identified in America back in 1907. It causes serious damage to bee stocks anywhere in the world.

AFB is caused by a spore-forming bacterium, Paenibacillus larvae. Spores are the infective stage of the disease, and infection begins when contaminated food is fed to larvae (up to 3 days old) by nurse bees. The spores germinate in the gut and bacteria move into the larval tissue, where they multiply. Infected larvae normally die after the cell is sealed and millions of infective spores form in the larval remains.

Diseased cells have sunken and greasy-looking cell cappings, and cell contents can be drawn out using a twig or matchstick, looking something like treacle. Dried-out cells have a thick, dark, ‘scale’ in the lower sector. A badly infected colony will have a strong, foul, smell.

Paenibacillus larvae spores are viable for many years, possibly as long as Anthrax, and are resistant to extremes of hot and cold and to many disinfectants.

European Foulbrood

The next worst disease our bees can get is European Foulbrood (EFB) which was identified in Europe by G.F. White in 1908. It is widespread, on all continents.

EFB is caused by Melissococcus plutonius bacterium. Larvae become infected when fed contaminated food by the nurse bees. The bacteria multiply within the larval gut and quickly out-compete the larva for food so developing larvae infected with EFB die of starvation. This normally happens shortly before the cells are capped – so beekeepers see dead and dying larvae in open cells. Colonies with an advanced infection will have a strong, and foul, smell.

More information about both foulbroods can be found on the NBU website. Check out the link on our ‘Links’ page.