American Foulbrood or AFB

AFB – American Foulbrood Disease

Found globally, although fortunately relatively uncommon in the UK, American Foulbrood can decimate a honey bee colony and rapidly spread to other hives, both in the same apiary and further afield. It’s a notifiable disease which means that, by law, you must contact DEFRA  immediately if you believe a colony is infected. Further information and contact details can be found on BeeBase here.

How to Recognise Signs of AFB in Honey Bees

There are a few key signs that you have an infected colony, these are:

  • Pepper-pot Brood Pattern – Alone this is not confirmation of American Foulbrood, as it’s common to many diseases, such as EFB and Chalk Brood, however it’s a definite sign that you need to take a closer look.american foulbrood infected comb
  • Sunken Brood Cappings
  • Perforated Brood Cappings
  • Dark Brood Cappings
  • Greasy Brood Cappings
  • Very Dark Scales – these will sit in the cells and be almost black in colour and unlike Chalk Brood (which is also different in colour in it’s early stages) are almost impossible to remove
  • The Rope Test – If you have any combination of the symptoms above, you should try a rope test, the short video below shows someone doing the rope test, so you can see exactly what to look for.
  • Testing Kits – AFB test kits can be bought online from Thorne and there are full instructions here from Vita Europe, the manufacturers, however my personal view is that if I ever suspect an infection, I would just contact DEFRA and have a Bee Inspector come out to confirm it, I’ve never done one before (and hope I never have to) whereas they have plenty of experience in identifying it.

In addition, as the name indicates a foul smell can come from the hive when opened, but bear in mind that this is often only in the more advanced stages of the disease, so the absence of the smell should not be taken as an indication that the disease is not present.

How Could My Bees Become Infected with AFB ?

It took quite some time for people to understand exactly how American Foulbrood was being spread across the UK,  an instance would pop up in Devon, then the next could be in Shropshire, then Humberside and next London. Obviously the bees were not covering this kind of distance and spreading it themselves, but there was usually no history of sales of bees or queens from one infected apiary to the next either.

jar of honeyIt’s now widely accepted that the disease is spread through honey originating from infected apiaries. Many of the countries from which the cheap supermarket honey is imported have quite a serious problem with the disease and because the spores are said to survive in honey for around 40 years, if our native bees find a discarded honey container which could be contaminated, they will carry the honey along with the spores back to their own hive and once there it can start a new local outbreak.

How does AFB Spread from One Colony to Another ?

There are essentially two vectors for the disease, the bees themselves and the beekeeper.

The Beekeeper

By moving hive parts (notably frames of comb) from an infected colony to an uninfected one, the beekeeper could easily transfer spores from hive to hive. Even using the same gloves and hive tool without cleaning them between hives can pass the infection around, so good apiary hygiene is of paramount importance in preventing the spread of not only American Foulbrood, but also the other brood diseases.

The Honey Bees

Once a colony is infected the bees will attempt to remove the dead larvae and scales from the cells, this causes them to inadvertently spread spores throughout the colony and into the nectar which is being ripened. Eventually the colony will die out from the disease, however as the colony becomes weaker other colonies will likely take advantage of the situation and begin robbing the stores from the failing colony and taking them back to their own hive, further san abandoned apiary can spread bee diseasepreading the problem.

Abandoned apiaries can also cause a problem, as if a colony became infected or an infected swarm were to move in to an abandoned hive, the disease would go unnoticed until it was identified in one of the robber colonies, by which point it could well have already spread to multiple apiaries. So it’s vital that unused equipment is cleaned and stored appropriately.

It’s also important that any swarms which are caught are isolated from your other colonies until you can be sure they are not carrying any disease.

You can download the leaflet about the foulbrood diseases from DEFRA here. You should also make sure you are registered with BeeBase, then you will be notified if there is an outbreak in your local area. We are lucky in this part of Wiltshire that there hasn’t been a case locally for several years, and compared to other parts of the country, have had very few cases at all, but that’s no reason to be complacent, although with a keen eye and good apiary hygiene, fingers crossed we can keep things that way.

A Final Point

AFB happens, there is no shame in finding it in one of your colonies and there is almost nothing which can be done to prevent it from arriving (although good hygiene will help to prevent it spreading), so if you suspect that it may be present in a colony, just close the hive back up, reduce the entrance of the hive to prevent robbing, do not move anything from the site and contact DEFRA immediately. The sooner it is identified the less chance it has of spreading.

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