O, Morphous mass!
On the bottom of the cell
Are you waiting for me?
Your body porridge
Slump. A foul fishy
odour of rotten flesh
And workers stamping
on your brown, lifeless mush
Leaving, as they leave,
A tiny imprint
“Here lays a fleshy worm.
slimy tongues poke out
or dry to a stale
I’m sorry, that was disgusting. What the hell was that!?
This, my dear readers, is the New Zealand Beekeeper’s Nightmare.
This is AFB, American Foul Brood Disease; or the “Aids of the Bees”. When there is AFB in the beehive, there is no cure. When there is AFB in the beehive, the only solution is to burn all the evidence.
In this weird poem I have described a few very important symptoms that help you identifying this disease. Symptoms are best recognised in the larval or pupal (post-larval) stage. To sum up a few:
Instead of a healthy pearly white creature that is curled up in a c-shape; the larva/pupa becomes
- Body porridge
- Slump: it lays like a flat mass on the bottom of its cell
- Stinks like rotten fish
- After a while the slimy substance dries up to hard scaly bits
However, these symptoms could be confused with symptoms of other bee diseases. This is why my poem ends with the one and only Definitive Symptom of AFB
- The Pupal Tongue. For some strange reason, a pupa that dies of AFB sticks out its tongue. It looks like a thin thread that points upwards in the cell. You rarely see it, but when you do there is no doubt: your hive is infected with AFB.
- Another way to identify the disease is by doing the “Ropiness-test“. This is shown in the picture above. To do this test all you need is a little stick; the foot of a match stick for example, or a piece of dry straw. You poke it into a suspicious looking cell. When you lift it out again and you see a brown slimy thread roping out, there is a good chance your hive is infected.
You can start raising suspicions by looking at the wax-caps that cover the brood. (This is only the case when the larva/pupa is 9 days or older). Symptoms that they might show are:
–Perforation. If you see any any caps with holes in it, it’s a sign that worker bees have “smelled” that something is wrong. They poke a hole in the cap and peer through it, to check if their babies are OK.
–greasy texture (instead of fluffy)
–grey colour (instead of light to dark brown)
–spotty cap pattern (instead consistent laying pattern; however this can also be a sign of a failing queen (see my previous post).
Note: You only have to find ONE infected larva or pupa in order to diagnose AFB. When this is the case, you have to burn the whole hive (according to New Zealand regulations). It’s a nasty process. You should pour petrol over the bees first, so that they suffocate. You dig a hole, throw in the hive and set the whole thing on fire.
What is the cause of all this misery?
It’s a bacteria. Paenibacillus larvae is its name. As it develops it appears in two different forms.
- Spore form. Like plant seeds with a hard outer coat. The spores are extremely strong: they can live over 35 years, and resist boiling water. The bee children get infected when nurse bees feed them honey and pollen with spores on it. One single diseased larva may contain more than 2.5 billion spores.
- Vegetative form: This is the bacteria as a reproducing agent. The spore has germinated into something that is replicating itself. It climbs into the gut of the young larva and when the larva matures to the (pre-)pupal stage, it penetrates the gut wall. It starts replicating more and more by consuming bee-tissues. Often it’s fatal. the vegetative rods turn back into spores when all tissues have been consumed. It means there’s no more food left for them. This is how the infection can start off with 10 spores and ends up with billions in one single bee.
Don’t think that bees let this disease just passively overwhelm them! They will do their best to get rid of it by taking away infected larva and excreting infected honey outside the hive.
Unfortunately, their attempts are not always successful…
Who’s to blame?
The most important source of AFB spread is the beekeeper!
- By switching extracted honey supers (boxes) between hives (often a year later)
- Transfer of brood frames between hives
At other times the disease spreads through the behaviour of bees themselves. The most important source is robbing. Robber bees are bees that infiltrate other hives. They ingest infected honey, take it into their own hive, regurgitate it there and feed to their brood. Robbing is usually how AFB turns up out of the blue in commercial operations.
Most of this information comes from the book “Elimination of American foulbrood without the use of drugs” by Mark Goodwin, Cliff Van Eaton, National Beekeepers’ Association of New Zealand. After studying this information I sat a bee disease exam, passed it, and this is how I became an “Approved Beekeeper”.