American foulbrood has been identified in two places near the city where I keep my bees, the hives infected have been cleared and there is a ban in place on moving bees within a 3 km (1.8 miles) radius around the effected hives. A little over a week ago the first two hives with AFB were found and yesterday a second outbreak was identified in a hive close to (but outside the 3 km “exclusion zone”) of the first effected hive. I read somewhere that all the hives in the apiary with an infected hive should be cleared but I can’t find clear information on this happening in these cases.
I never paid much attention to the mad cow disease and swine flue scare, but now that it actually concerns animals in which I am invested and have a vested interest I do care. Perhaps a little hypocritical of me but that is just how it is.
American foulbrood is a disease caused by the spore forming bacteria; Paenibacillus larvae, which can stay dormant in your hive for years before it becomes active. I haven’t found what can instigate an outbreak but perhaps as with DWV which will only effect hives that have been weakened by say Varroa. A healthy colony with a healthy grooming propensity can be a carrier of the disease without being effected by it.
The spores produced by this bacteria don’t effect adult bees but to young brood it is devastating. Larva can be infected by food that contains spores. Larva younger than a day are easily effected, but 4 day old larva are orders of magnitude less likely to get an infection from the spores.
Finding a weakened colony with very little open brood can indicate that the colony is infected with this disease. The hive will seem lifeless and the caps on the closed brood will have holes or tears. The “matchstick test”, poking in a cell with a torn cap, will produce a yellow brownish goo (as seen in the image at the top).
In The Netherlands informing the authorities of an AFB suspicion is mandatory. Although it is unclear to me how many beekeepers stick to that rule. I guess all the beekeepers here in the north of the country are on alert.
Hope for the best,
(Dutch version: link)
Addition1: I visited the bees today and there was no sign of AFB in either hive, I did see a DWV bee walking on the frame in Artemis. This might be a sign of Varroa infection but I began my treatment against Varroa when this bee was perhaps a larva (bees with DWV don’t tend to live long, they will be removed from the hive by other bees). So this is not a sign of the actual Varroa pressure at this moment, I hope. Sif which does have a bottom board to catch the mite drop did have some mites in the three weeks it was under the hive but not a ridiculous amount. Not like the first time I treated Sif a little over a year ago (no pictures).
I also did a quick assessment of the stores of both colonies to get an impression of how much I will have to feed them. I think they have about 7 frames of honey between them, Sif a little more than Artemis but I will divide the honey evenly and feed them both the same amount of sugar syrup. I expect that about 10 kilogram sugar each should be enough to get them through winter.
I’ll post new AFB developments here.
Postscript: I talked to a more experienced beekeeper at the apiary yesterday (21/09/14) and he told me that a colony with AFB isn’t necessarily lost. What you can do, according to him, is make a “Shook Swarm” of the entire colony then leave the colony in a ventilated box for an extended amount of time till the first bees start dying from starvation.
You do this because the AFB spores live in honey surrounding the brood nest and to be sure the spores are gone the bees in the shook swarm need to burn through all the honey they have in their stomach. Then the bees will be free of AFB and you can put them into a clean hive.
This method seems somewhat iffy to me as it seems easy to either kill the colony or still leave them with honey infected with AFB, I hope I never get the opportunity to try this method.
Addition2: (07/09/14): There has been a second outbreak of AFB in a town called Exloo, which is about 50 kilometers (≈30 miles) form my home town. For me in the right direction compared to the last case which was about 16 kilometers (10 miles) away.