American foulbrood (bees)

About American foulbrood

American foulbrood (AFB) is a disease of honeybees caused by a spore-forming bacterium called Paenibacillus larvae. This bacterium forms spores when subjected to stress such as lack of nutrients. It's these spores that actually cause and are the source of the disease. 

Spores enter the larva through feeding of contaminated food. The bacteria kill the bee larva by completely consuming the body tissues.

The spores are highly resistant to extremes of temperature, chemical attack and other adverse conditions and can remain viable for many years. Once hardship has passed, for example, when nutrients become available again, the bacterium will germinate and reproduce. The cycle will repeat if hardship occurs again. This means that it is difficult to eliminate the spores from colonies.

There are no public health implications from AFB.

In 2010 the island confirmed Amercan Foulbrood, the outbreak was brought under control however confirmed cases do occur from time to time.

Spring update letter 2019

Island map of infected apiaries 2014

Island map of infected apiaries 2013

Island map of infected apiaries 2012

Island map of infected apiaries 2011

Island map of infected apiaries 2010

Symptoms

When infected larvae die within the sealed cell, the appearance of the cell cappings changes. The cappings become:

• sunken and perforated when adult bees nibble holes in them to try to remove the infected larva within
  
• some become greasy looking and slightly darker in colour than other cells

In the early stages, these changes can be quite delicate and only detectable by careful inspection.

Protect livestock

Cleaning and disinfecting tools

A solution of washing soda in water is recommended to disinfect tools. A concentration of approximately 1 kg soda in 1 gallon (4.5 litres) is suitable. Adding a small amount of detergent (washing-up liquid) to the solution will help with cleaning.

If you prepare the solution in advance you should label the container ‘washing soda solution’ and include the date of preparation and expiry (maximum of 1 month from preparation).

Immerse the tools in the solution and, using a scrubbing brush, scouring pad or similar, scrub off residues until the tools are clean.

Tools can be left soaking in a container of washing soda solution when not in use or when in transit between apiaries.

Discard the solution when it becomes discoloured or after working in an apiary with foul brood infection.

Cleaning gloves

To clean gloves:

• immerse the gloves in a container of washing soda solution as detailed above
• rub the fingers together or scrub with a brush or scouring pad to remove traces of honey and propolis
• strong rubber gloves can be washed in a washing machine with beekeeping overalls

Cleaning boots and smoker

Remove traces of honey and propolis by scrubbing in a solution of washing soda (as above).

Cleaning bee suits, boiler suits and veils

These cannot be adequately cleaned in the field although traces of honey can be removed with water. Wash in hot water with detergent in a domestic washing machine. Follow the washing instructions attached to each garment. It may be necessary to wash veils by hand if they are unsuitable for washing by machine.

Washing hands

Wash hands using soap and warm water. Do not use cleaning agents not intended for use on the skin as these may cause skin irritation. 

How the disease spreads

AFB can be spread when combs, honey or hive equipment are transferred from an AFB-infected colony to a healthy colony. Bees robbing honey from infected colonies also transmit the disease. Swarms from infected colonies may also carry infection with them and become diseased after they are hived.

If you collect a swarm of unknown origin, the hive should be kept isolated at a separate apiary for at least 12 months to enable disease and quality checks to be completed before considering introduction to established apiaries. A new apiary must be registered with the Animal health and Welfare team as soon as possible and in at least 28 days.   

Hived swarms should be assessed after 6 weeks and any colonies showing signs of serious disease should be destroyed. Only when satisfied that they do not pose a disease risk should movement to another apiary be considered. 

Beekeepers should ensure that all relevant bio-security and bee hygiene measures are taken.

Controlling AFB

AFB is a notifiable disease meaning it is subject to official controls including compulsory destruction of infected colonies.

Destruction is by burning, where possible in a pit adjacent to the hive, under the supervision of an authorised person. You must take precautions to prevent spread of fire and you should notify the Fire and Rescue Service in advance. Alternatively, arrangements can be made to double bag material and incinerate it at the Energy from Waste Unit at La Collette.

Hives and appliances can be sterilised by thoroughly scorching them with a blow lamp. Gloves, overalls, footwear and the smoker should then be washed thoroughly in washing soda or hot soapy water. Care must be taken to ensure that plastic, rubber or other materials likely to produce noxious smoke are not included in the burning requirement.

It is also not practical to scorch polystyrene and non-timber hives by fire and these should be disposed of in a way that ensures that the end point of disposal is at the Energy from Waste Unit at La Collette.