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Discussion Starter #1
I started two nucs in a new yard with bought queens at the beginning of August. They were joined by a queen from a failing hive that I put in a nuc to use in an observation hive. I say this because she and some of her frames may have been the source of the EFB (European Foul Brood). I noticed the brood pattern in both nucs deteriorate and two weeks ago I started thinking about EFB. I Confirmed with my mentor this weekend that it is indeed EFB. I took out a couple badly affected frames and began to feed. I ordered terramycin. I started feeding syrup and patties. The nucs are five over five and have almost drawn out all the frames. The badly affected hive has three frames of foundation now to work on. It has symptoms throughout. The other nuc only has a few cells affected. I need both to over winter together.

My question is should I scrap the nucs and start over in the spring? How likely are they to have reoccurring symptoms if I keep the comb? Would you feel safe overwintering them on another colony if you had plywood in between? I don't want to bring it to my other yard. It's been hot here, and we probably have another month left to feed. I would like to hear from people with experience dealing with EFB.

Thanks!



 

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Yes SORRY you MAY have a EFB problem as it looks from your pictures you could confirm by asking your bee inspector or a experienced bee keeper from your area to double check in the mean time you should close up you hives until checked to prevent hive robbing! You should NOT inter change any equipment, hive parts ect UNTIL you have treated and your hives are free of EFB You may also have to burn ALL of your Brood Frames foundations, and Honey frames foundations and Scorch the inside of your wooden ware (HIVE Boxes ect)
Also worth reading the following post that on now Newbees, Mediums and AFB -- a cautionary tale
 

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Discussion Starter #3
Like I said I am interested in hearing from people who have experienced EFB European Foul Brood. Not to be confused with AFB American Foul Brood. Thanks!
 

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Margot
Enclosed is a fact sheet on EFB It states that you should BURN the affected frames as you would AFB (also refer to post in previous link as I have provided a link to EFB and AFB) Also you may refer to CAPA Publication :"Honey Bee Diseases and Pests 3rd edition MB may have in his book store) I have over 30 years as a bee keeper and worked with bee inspectors.

EUROPEAN FOULBROOD Disclaimer: Fact sheet text / pasted from BC Ministry of Agriculture

European Foulbrood (EFB) affects bee brood and is caused by the bacterium Mellisococcus pluton. The disease has been reported worldwide and is generally not considered serious. EFB incidence is generally higher when the colony is under stress due to poor management, lack of forage, high colony density, prolonged damp weather, etc. EFB most often occurs in spring but has also been reported in late summer.

Young honey bee larvae become infected with M. pluton when they are fed contaminated food. The bacteria multiply rapidly in the mid-gut of the young larva, resulting in starvation just prior to capping. Some larvae may survive and enter the pre-pupal stage but die shortly thereafter. The bacteria can remain viable for several years after the larva has died.

Symptoms

When the larva dies, it is in the coiled or twisted position and will turn yellow to brown. It is suspected that prior to death, the larva becomes restless and twists and turns. Approximately 10% of the larvae die after capping and this often leads to misdiagnosis because of the similarity to symptoms of American Foulbrood.

The odour of the infected brood is sour. Unlike American Foulbrood, EFB-infected larvae don’t become ropy when a sample is collected from a brood cell. Over time, the decaying brood will dry up and form a rubbery scale, not brittle like AFB. The scale is easily removed from the cell and used for microscopic examination.

When in doubt, collect samples from several cells with a toothpick and place in a small plastic bag or plastic wrap. Place the sample in an envelope and mail to the Apiculture office in Abbotsford for identification. (Note: M. pluton is generally not microscopically identified but instead, the secondary invader Bacillus alvei is, characterized by its large spindle-shaped spores).

Management and Control

At the start of the main nectar flow, EFB mostly disappears or becomes non-detectable. The infestation may reappear in the fall. Re-queening seems to help because certain bee lines appear less susceptible than others (due to cleaning behaviour), and the replacement of the queen involves a break in the brood cycle of the colony.

For cleaning up an active EFB infestation, all frames with significant numbers of affected cells should be removed and burned.


The recommended amount of antibiotics should be dissolved in 250 ml of sugar syrup and sprayed or sprinkled onto the adult bees at least twice, 4 days apart (refer to Factsheet #204 for dosage and handling).

Prevention
•Inspect brood frames regularly and be familiar with field symptoms.
•Inspect frames before transferring bees or combs between colonies.
•Minimize robbing by preventing syrup spillage. Do not barrel feed. Keep apiary clean and remove unused and old equipment.
•Establish hospital yards for colonies from different apiaries that have EFB. Clean hive tools, smoker and gloves after inspection of each apiary. Clean clothes regularly.
•Replace the queen every 1 – 2 years.
•Feed only clean pollen and honey to colonies.
 

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Burn the frames.

The labor required to sterilize nucs (Glacial acetic + Scorching the boxes) isn't worth their value, so burn them too.

The recurrence on shook swarms is 4% and on TM treated original frames is 21% (per British statistics). You don't have the season to do a successful shook swarm.

EFB is not spore forming, but live bacteria will reside in the rubbery larvae mummies for a long time.

EFB is ubiquitous and partially a stress disease, but a heavy infectious load is going to reassert, and the problem becoming worse with each infection cycle, as more and more of your equipment carries bacteria. EFB induction is a good reason to cut out that yucky black comb that develops by year 4.
 

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I've had EFB. I would not burn your frames. Cut out the infected comb. Much is written on it and it's up to you which route to take.
 

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I've had it this year as well. and I inadvertently transferred it to an adjoining hive. One hive recovered well, the original weaker hive struggled all season, even with new comb and three different queens. My searches indicated EFB DOES NOT FORM SPORES. Curious to see if it reoccurs in the spring when the hive is stressed by build up. There are conflicting anecdotal stories as to whether or not it overwinters, and if small populations and stress will lead to reoccurrence. The bees have cleaned out the infected larvae, but some bacteria may be present in the stored bee bread.
 

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To my old eyes those larvae still appear white. Are you seeing off colored larvae? Do your hives have an unpleasant odor?
And last but not least.....have you done any sort of mite testing?
 
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Good point Dan. Differentiating between efb and pms can be tricky as high mite loads can also be a stressor that can lead to efb. I don't claim to be an expert but when I see hives stressed with high mite loads this time of year they can look much like this but they generally have a disproportionately high amount of eggs and open larvae, as if the queen is desperately trying to regain population. The pics are showing just the opposite, a backfilling of the brood nest. I'm not saying that is definitive but to suggest that the op should start burning based on one opinion and sketchy evidence seems a bit draconian.
 
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Differentiating between efb and pms can be tricky as high mite loads can also be a stressor that can lead to efb.
Indeed. In the past few years I've seen several cases of EFB that I was able to associate with high mite loads. I will also say, in those cases the colonies were beyond saving.
I've never burned EFB comb. I've gone so far as to move it to strong healthy hives and don't recall any noticeable carry over. Do you recommend burning?
Now...AFB would be a different matter.
 

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does anyone know if freezing frames infected with efb will kill the bacteria? perhaps letting ants clean up the frames? for newbees comb is a precious commodity and worth saving, but not if it means putting healthy colonies at risk.

we had a contributor (forgot who) a few months back who was claiming 100% success overcoming efb by pinching the queen and combining a queenright nuc.
 

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Indeed. In the past few years I've seen several cases of EFB that I was able to associate with high mite loads. I will also say, in those cases the colonies were beyond saving.
I've never burned EFB comb. I've gone so far as to move it to strong healthy hives and don't recall any noticeable carry over. Do you recommend burning?
Now...AFB would be a different matter.
No, never burned efb but some seems to pop up most years and will usually go away just as quickly if/when forage conditions improve. If it seems debilitating mid summer we will treat individual cases with tm and leave honey supers off. Not saying thats right or wrong only from a commercial pov thats what is most efficient.
 

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I, too having been waiting to read/hear about freezing. Glacial acetic acid or irradiation seem like generally accepted methods of treating frames. I did cross infect a second hive by giving suspected frames (two) to it. Apparently, the hive wasn't strong enough to clean it up, at least not for a while. I did the strong hive/feed syrup if not in a strong flow and requeen protocol. With rumors of EFB infected hives coming back from almonds, and some of those hives making their way around as splits or being sold outright, EFB seems a growing concern, at least locally in my region
As an addendum, while not all bacteria are created equal, I see that both salmonella and e.coli survive freezing. Labs store bacteria down to as low as -80. My home freezer certainly can't to THAT.
 

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I understand that to err on the side of caution, destroying the comb is the answer. Some years ago I had a round of EFB spread throughout one of my yards. I treated all of the hives with tm per instructions and it disappeared. It never returned nor did I ever have to retreat those hives.
I do think that freezing frames would do the trick too. Also, overwintering the frames in a stack of boxes with some PDB in top would work, I believe. The bacteria is not long lived without a host. I guess it all depends on the beekeeper's philosophy about such things.

Back to my original question for the op. Do you see any discolored larvae? Does the hive smell? And have you done any mite testing?
 

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What I see in the third image is consistent with EFB, and differentially not like Varroa mite syndrome.

I annotated a detail from the image.
I see "cream" larvae forming large triangular mummies,
I see twisted (starved) larvae,
I **do not** see the white guanine flecks characteristic of a Varroa killed comb. (but the straight-on image may prevent observation).
I do not see sunken perforated caps or watery discolored caps (AFB indication, and Varroa virus indication).




I have observed a large number of hobby apiaries build up EFB. The commercial dosage of TM may prevent this, but the hobbiest don't tend to use it effectively or at all, and once established in a small scale apiary, the frames get carried to new hives, and gradually the problem gets worse and worse. Individual hives fail to thrive and die (sometimes remarkably quickly), and the overall level of infection increases over time.

Rolling over the frames by cutting out the black combs is good practice -- would be interesting to learn if EFB is avoided in Top Bar. Logically there should be a far lower incidence on crush-and-strain systems.
 

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I have treated it and not had it re-occur most of the time. I did have one hive that it showed back up in almost as soon as the antibiotic was done. We burned that hive.
Dave
 

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Discussion Starter #17
Thanks for all the comments. These nucs came from frames with low mite counts. I have not tested them, they have only been in existence a month. I am pretty certain it is EFB and not mites but I will do a drop count to be sure. Luckly, we are talking about two nucs, a total of 20 frames. I will treat with the antibiotic and see if I can get them to over winter. Would you feel safe overwintering them on a hive with plywood between? If they die, I will destroy the comb and start over. I have to do some reading about EFB as well. Burning frames seems over board. I was told by my mentor that EFB does not transmit on the frames, only the comb. But I will do my research. Thanks!
 

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i've dealt with plenty of efb. It can show up at any time once an apiary has been infected. I've tried freezing, acetic acid and everything else but am not convinced that I have been able to disinfect frames as I have had cases show up in otherwise clean hives shortly after adding suspect frames. I have also had it clear up in hives and not return for some years without treatment. After fighting a serious infection that took half an apiary out of production this spring I began to learn to see EFB coming on. Any spottiness in brood and/or yellowing of larva will nearly always be followed by a serious infection a week or two later. I've come to the point that I will treat with tm spring, summer dearth and fall once efb is in an apiary and particularly in hives with a history of infection. Infections are cleared most quickly by treating with tm in syrup (It is important not to add the tm while the syrup is still hot). The dusting method every five days for several weeks seems to work as a preventative in hives with little or no outward symptoms.

EFB works by bacteria competing for food in the gut of the larva. The larva starves to death. It may appear to disappear during nectar flows because the larva is fed more and therefore does not starve. In nectar dearths or in times when there are not sufficient nurse bees it rears its ugly head again. I also suspect that bees that have the bacteria but which managed to pupate and hatch are debilitated (and are shorter lived) by the lack of nutrition. Oxytetracycline works not by killing the bacteria but by inhibiting its reproduction and consequently the bacteria is suppressed but is never completely eradicated. I have watched enough colony collapse in my own apiaries that I am now convinced that a great deal of colony collapse in August and September is from efb due to a nectar dearth and/or stress from mites and built up efb bacteria levels in the hive. Last year by this point I had lost 20% of my hives and would lose another 15% by the early spring due to colony decline. Most of them at some point showed spotty brood, yellow brood and melting brood. I tried treating sick hives with tm and saw improvements in brood only to have the hive so weakened that it would be overcome by beetles and/or robbing. The problem is that I was responding once the hive was in serious trouble. That was the wrong approach that I determined to change after another bout with efb in some hives this spring. By applying apivar after the spring flow in June for mites, taking on efb by dusting TM in July (and watching hives closely for this disease all summer), and by being more proactive in feeding light hives all summer I reduced mite and efb stress and provided the feed to maintain a steady brood production. Consequently, I am looking at booming hives with zero losses out of 90 hives as of today. That is a tremendous contrast to the late summer losses I had experience the previous four years.
 

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Discussion Starter #19
Last inspection the nucs looked better, I have been feeding heavy and I will treat with TM this week. Thank you Tim B, your explanation of how the bacteria works is very helpful. You speak of a whole apiary being affected rather then individual hives. Have you noticed it spreading to other hives that you did not directly transfer comb to? I have been told that EFB is rare in my area, and like you said appears and disappears with dearth and flow. If you were me an only had five hives and were starting a new yard with two nucs that had some EFB would you just destroy the nucs and make a clean start in the spring. Would you take the nucs to your main yard to overwinter on a strong hive or would you just let them tough it out? Thanks! Margot
 

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Efb does at times seem to jump from one hive to the next in a given apiary. Spring infections seem to show up in hives with older frames. Summer infections tend to pop up in those hives and in nucs and other new hives. I wouldn't combine hives with known infections with hives that do not seem to be infected. It can be cured and not reappear but it often does. Once it gets established it seems like you will have to treat at least spring and summer dearths to beat it back. For me EFB has been serious the past two years costing spring production in as much as 20% of my hives and possibly killing off 20-30% until preventive efforts this year. If I have a rash of infections in the same hives again this spring I'll probably start burning frames or quarantine those hives to another yard, treat them every couple of months and use them for something other than honey production.
 
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