I think a lot of bee disease is stress related and for that reason alone it is good to minimize disturbance**, disruption, heavy handling, opening on cold days etc.
I have read, may be another myth, that foulbrood spores are usually present in a colony, same as nosema spores, but it takes stress to raise the spore count to a critical level and induce the symptoms of the disease.
**Not yet advocating let alone beekeeping
Yeah, I have read that too and had it quoted at me from people who should know better. Simply don't believe it. EFB is missing from large areas and is still actively colonising parts of the UK. Once it it there it may bubble up again from latent infection (eg contaminated comb) but I don't believe that it is near-ubiquitious and awaiting stress to trigger it. Tooth fairy stuff.
Hardly tooth fairy stuff, it just needs a little qualification to make it entirely accurate.Originally Posted by gavin
If the causative agent, melissococcus plutonius, is present at a sub clinical level then a stress event (typically a dearth of food when there is brood to nurture) can trigger a clinical outbreak of what we know as EFB, of course if the causative agent isnt present it wont magically appear out of thin air.
Colonies with AFB frequently get up to swarming strength and swarm if they go undetected, the 'dont feed a swarm for a couple of days' tip is a percentages thing, we may as well make it less likely that anything is passed from one generation to the next ( vertical transmission).
Finally, the forest fire/smoke thing will never be known unless bee psychiatry jumps to fantastic levels where we can really plumb the depths of a bee's mind, my money's on it being partly true and the confusion caused by the foreign smell of danger helps distract the bees from defensive behaviour.
If you gather a swarm that is of unknown origin you have two choices to try and protect yourself from them bringing (possibly large levels of) FB spores with them.
1. Burn a sulphur strip in the swarm box after collection (with the bees still in it)
2. Starve them a bit
choice one is 100% sure to protect you
choice two is a percentages thing
Lol, yes.
This linky:http://pub.epsilon.slu.se/1053/1/Avhandling.pdf is a paper I keep going back to to explode some myths about AFB, our own NBU seems scared to tread on this ground in case beekeepers twig their colonies need not necessarily be destroyed if they have AFB and they can rid themselves (sometimes !) of the infection given a fresh start on clean comb.
Great find that paper, MBC. First time I have seen it.
It certainly backs up what Calum suggested about not feeding a newly housed swarm.
Page 18
It also shows that there are AFB spores in a colony without symptoms necessarily being present.None of the swarms showed any clinical disease symptoms at any time. This indicates that the amount of spores
needed to produce clinical disease are not transmitted by swarms, or at least that they are not readily available to the larvae. If clinical symptoms appear, it is on a non-detectable level. It seems reasonable that a “no brood, no food” argument is
valid here, as well as in the artificial swarm case. Because the bees do not have
any stored food they will consume whatever contaminated honey they have in their
honey sac. Also, there are no larvae available to the swarm to which they can
transmit spores before most contaminated food carried from the mother colony is
consumed.
Page 14
Twenty-two percent of the individual colonies
were clinically diseased. All samples from clinically diseased colonies were
positive. Of the remaining colonies, 77% were positive although they had no
visible symptoms of AFB. We found a significant relationship between the number
of clinically diseased cells in the colony and the number of colony-forming units
(cfu) in the laboratory cultures. Colony-forming units are the number of bacterial
colonies that grow on the agar plates.
Fifty-four percent of the apiaries contained clinically diseased colonies. In the
lab cultures, however, 70 % of the clinically healthy apiaries were positive for
AFB.
Last edited by Jon; 11-05-2012 at 09:53 AM.
Glad to have the qualification (and that was always missed out by those I heard talking about this), but from what I know of the disease I'm unconvinced that stress triggers a build-up. Seems to be true for chalkbrood (at least, damp weather and low income seems to help that one). Levels of EFB locally seem to wax and wane and I'm far from convinced that dearth has a big role. Is there any real evidence for this? Yes, the disease often seems to appear at the end of the spring flow, but this doesn't mean that stress is involved. Maybe the bees that are being hygienic are distracted while there is a major flow on and the levels build up then. I should say this is more speculation, not fact.
Feed the bees, we've been told, and the disease will decline or not appear. Happy to be correct (as always) but I don't see it.
Need to be careful. We are talking about both AFB and EFB now and the same logic may not necessarily apply to both.
Regarding EFB my understanding is that a good flow can mask the problem in the short term but makes it worse later. The reason is that with EFB the larva usually starves to death before being sealed due the the fact that the bacteria rob the food from its gut. With a good flow on the bees can overfeed to compensate and the larva dies after reaching the pupa stage. At this pint the doomed larva has already voided its gut and filled the cell with millions of bacteria waiting to be spread by the house bees when they clean it out.
I suspect the thinking that foulbroods are in every colony at sub-clinical level applies more to countries that do not employ our strict policy of eradication.
Rosie
Not sure Steve. MBC's link referred to Sweden.I suspect the thinking that foulbroods are in every colony at sub-clinical level applies more to countries that do not employ our strict policy of eradication.
Treatment and control
In Sweden, no treatment is allowed for clinically diseased colonies. Instead a
stamping out policy is employed, which means that the bees have to be destroyed
and the contaminated equipment destroyed or thoroughly cleaned (Anon., 2002).
Several treatment strategies are allowed in other countries, such as treatment with
antibiotics and apicultural techniques like artificial swarming. Treatment with
antibiotics is not allowed in the EU, but is common in, for example, USA and
Canada where preventive treatments with antibiotics is considered a routine
procedure to avoid outbreaks of AFB. Not surprisingly, antibiotic resistant strains
of P. larvae have evolved (Miyagi et al., 2000). Another problem with this
practice is residues of antibiotics in honey and other hive products (Bogdanov,
2006).
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