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CONTROLLING AMERICAN FOULBROOD WITHOUT ANTIBIOTICS AND WITHOUT KILLING THE COLONY

A response to the informative article by Cliff van Eaton in BfDJ 91

Ole Hertz, Apicultural Consultant, Skovshoj, Gudjemvej 50, 3760 Gudhjem, Denmark

American foulbrood (AFB) used to be a serious problem in Denmark.  For more than 30 years this treatment without use of antibiotics and without killing the colony has been used with great success by beekeepers and government authorities responsible for fighting the disease.

It is a pity to destroy a strong colony and it is not necessary. Only very weak colonies unable to survive the treatment have to be destroyed. 

The Danish method for treatment of a strong colony with AFB is:

• All mature bees are brushed into a clean box or hive with top-bars or frames equipped only with strips of wax as starters. A sheet of newspaper or plastic is placed under the box to collect drops of honey with AFB spores. The bees build new combs and use all the honey they have in their honey stomachs. This must be done where the chance of robbery from other colonies is minimal.
• Brood combs and honey combs are burned. Brood can first be killed with petrol. After four days the bees are brushed from the combs into a cleaned hive with new wax foundation. Again, any drops of honey are collected on a newspaper in the bottom of the hive. Now the bees are free of most spores, and the colony can if necessary be fed artificially.
• Because the vulnerability to AFB is partly genetic, it is recommended to change the queen.
• Combs with honey from the box are melted and the frames cleaned by heat and fire and are disinfected.  In Denmark, the biological cleansing agent Vircon S is recommended.

 After AFB is detected in an apiary, all other apiaries less than 3 km away must be inspected by a beekeeper trained in disease detection.  If new AFB colonies are found, they must be treated, and all other colonies within 3 km must be investigated.

The government pays for this work and a beekeeper receives a small compensation for the loss. Analyses for AFB spores in honey imported into Denmark show that 90% of all samples are contaminated, while only 30% of Danish honey carry spores.

References

MINISTRY FOR FARMING (2009) Instructions for trained beekeepers.  Copenhagen, Denmark

VEJSNÆS, F.; SØGAARD JØRGENSEN, A. (2006) Bisygdomme,(Bee diseases), Tidskrift for Biavl 3.