American Foul Brood (EFB )
In the UK this is a notifiable disease
- If you suspect your hives have AFB then:
- Reassemble the hive.
- Wash and sterilise all equipment
- Notify your Regional Bee Inspector
- Frequency
- In 2024 there have been many ofccurrences.
- In 2024 there have been 58 cases in the UK
- In 2023 there were 82 cases in the UK
- It is not common but it does happen - watch for it
- Full details can be found on Beebase.
- Cause
- Spore forming bacteria Paenibacillus larvae
- The spores can remain viable for over 50 years
- Spores very resistant to extreme temperatures.
- It is not thought to be stress related.
- Estimated just 10 spores fed to a day old larva will infect it.
- Effect
- Larvae consume contaminated food
- Bacteria multiply in the gut tissues
- Infected larvae usualy die after cell capped
- AFB - After capping Foul Brood
- Dead larva dries to a scale
- Scale contains infective spores
- Scale cannot be removed from cell by workers.
- Infection spreads rapidly through the colony
- Infection can take several months to destroy colony
- Symptoms
- Wax cappings of brood cells sunken
-
- Because the larva has died and is drying out.
- Wax cappings of brood are perforated
- Because workers are trying to remove the dead larva.
- Holes in capping are jagged and irregular.
- Wax cappings of brood may be darker and greasy looking.
- Under sunken capping larva look brown and slimy
- Diagnosis
- Perform a rope test
- Insert a matchstick into the suspect cell
- Draw it out slowly
- A brown mucus thread 10 to 50 mm long indicates AFB
- In a cell you may see:
- In pupal bee the proboscis may be visible
- A brown scale near the top of the cell.
- In AFB scale is brittle
- In EFB scale is rubbery
- Can be confused with sacbrood virus
- Treatment
- There is no treatment.
- Call the bee inspector
- What the Bee Inspector (England and Wales) does
- a full hive inspection will be done
- a Lateral Flow Test will be done
- If AFB unproven a sample will be sent away for further analysis
- If AFB confirmed the colony will be destroyed and the contents burned in a pit.
- In some cases the complete hive will be burned.
- In other cases the hive will be sterilised with a blow torch.
- Why not use antibiotics?
- In the UK the use of antibiotic treatment is banned because:
- It masks the symptoms but does not control the disease
- The spores are not destroyed
- Antibiotics do not clean the contaminated equipment
- Antibiotics may contaminate the honey
- Antibiotic resistant strains may form.
- Prevention
- AFB is not highly contagious
- Spread mainly by beekeepers moving spores on comb or equipment
- Can also be spread by bees robbing and drifting.
- Check the NBU website for incidence reports