We mentioned that one of the hives at the Gardens had a VERY spotty brood pattern and we were concerned and watching it. After a few inspections, this hive was lagging behind and the brood pattern was not improving. We began to worry there might be a more serious issue.
This is where having more than one hive comes in handy…comparing progress with the same sets of circumstances: cold, nectar flow, drought. This allows you to identify if one is DRASTICALLY different than the other. See below – the brood pattern in the package we purchased and that of the hive with very spotty brood.
You can see the difference. It isn’t in the color of the cappings, it is in the amount of space between the capped cells. A few cells are more typical of a healthy hive…nurse bees removing unhealthy larvae. The bottom photo is a different circumstance. With what is capped there aren’t really enough bees being produced to replace the older generation. Something was happening here and we needed to find out soon.
If you are a beekeeper, you know that hive inspections have a couple of purposes. To make sure they have enough room for the queen to produce more bees AND for the foraging bees to store resources pollen and honey (for themselves or the beekeeper). This must be in balance for the hive to continue to thrive. The other reason is to keep an eye on the health of the hive. Many things can cause a decline in health or indicate an issue that must be addressed. In past, we have discussed the Varroa mite and damage they can do to a hive by weakening bees directly or vectoring (transmitting) diseases. There are others though including: hive beetles and wax moths which will damage brood and honey cells, but a strong hive can usually keep those populations down to a manageable level. Then there are those that are invisible, but have signs that beekeepers need to watch out for. Nosema dysentery, a spore-forming fungal parasite that causes essentially bee diarrhea which if bad enough can cause nurse bees to not be able to rear the brood – particularly problematic in fall, winter, or early spring.
Finally, we come to the Foulbroods: European Foulbrood, Melissococcus plutonius (EFB) and American Foulbrood, Paenibacillus larvae (AFB). Both of these are bacterial brood diseases that weaken and have the potential to kill honeybee colonies. The beekeepers at Dow Gardens (Elly-15 years or Debbie-3 years) had never encountered conditions indicative of either of these brood diseases…until now.
The brood pattern in the nuc was of concern after the first inspection, however, we COULD have been seeing some impacts on brood from the cold, chilly weather. So we gave the hive a bit of time to rebound. At the same time, nucs from the same supplier had been placed into both of our personal apiaries and the similarities in brood issues began to cause concern.
We did what we always encourage our students to do…research, research, research…and when all else fails reach out to a beekeeper with more experience.
Spotty brood pattern
Dead larvae that didn’t reach capping stage
Dead larvae were decaying in the cells some rubbery and some ‘snotty’
WHAT WE DIDN’T FIND
Foul smelling brood
Lots of sunken caps on the brood
Dead/dying bees in quantities
Only some of the hives seemed to be struggling to keep up their numbers, others seemed fine based on traffic at the entrances and number of bee seams
With the lack of a foul odor and it not looking super dire, it was easy to try to dismiss foul brood, but there was this nagging feeling. The research was a bit defeating and confusing at first. Lots of opinions about what to do about ‘foulbrood’…everything from kill all of the bees and burn the hive to just requeen and they will be fine – in between was treat with antibiotics (which you cannot get without essentially a prescription from a bee vet). Who has a bee vet??
As a biologist, none of this set right with me, so I delved deeper into EACH type of foulbrood. As I did, I realized they are SO different. This was the reason for such a range in treatments for ‘foulbrood’.
American Foulbrood (AFB) is caused by a bacterium, that when conditions are not ideal for reproduction, they will form spores which are viable to cause reinfection for over 50 years (some say for 70 or more) and are resistant to freezing and high temperatures…durable little bug. It is highly contagious and can spread from hive to hive through robbing behaviors, contaminated equipment (swapping frames between hive – a common practice in an apiary) or even the hands of the beekeeper. This infection – based on my research – requires killing all of the bees when as many of the foragers are in as possible and then burning all contaminated equipment in a hole, burying what is left so any honey residue will not be consumed by foraging bees in the area.
European Foulbrood (EFB) is caused by an entirely different bacterium that does NOT form spores. It is highly contagious and can remain viable for several years in honey, wax and equipment. They can be infected and show no visible signs until the hive is stressed, then they can have a sudden outbreak. The treatment for EFB is to treat with the antibiotic Terramycin, feed the hive to encourage more egg laying by the queen so the healthy brood can outcompete the ill ones, and shaking adult bees onto clean foundation and disposing of old comb. Some suggest requeening, however, since the infection happens between the nurse bees and the larvae, I am uncertain about why this is recommended. Some suggest mild infections may clear up on their own with a good nectar flow and providing feed.
This information is sifted down out of DAYS of research and I encourage you all to do your own reading on the subject. You can see why this is so confusing and the prospect of either of these is pretty daunting. The only one that has a true formula for treatment is the AFB…and that is quite literally a death sentence.
We had to get to the bottom of the mystery so we knew HOW to deal with ‘whatever’ was causing these obvious symptoms in our hives, and not lose ALL of the bees in our care.
We called in the BIG GUNS…that would be Dan Keane, a 40-year beekeeping veteran that was a state bee inspector in his younger years and a great mentor to consult with. He visited one of our apiaries and help inspect the hive of concern. He spotted some chalkbrood mummies and upon inspection found only one or two sunken brood caps. Dead larvae will “rope” meaning that their remains will stretch out if you poke them with a stick and gently pull. He didn’t think the dead larvae were the right consistency to exhibit the ‘roping’ indicative of AFB (see image below). He determined it is most likely European Foulbrood and that we should treat the hive with antibiotics. Thank you, Dan, for helping to rest my nerves with your expertise.
Roping of dead brood on a toothpick; not long enough to indicate AFB.
CONFIRMING a diagnosis:
There are a variety of ways to confirm a diagnosis. The first and most scientific is to send a sample to the United States Department of Agriculture Bee Research Laboratory in Beltsville, MD for culturing. We are doing this! Here is a resource with the directions about how to do this if you suspect something. Not only can they diagnose WHICH foulbrood disease it is but also whether the strain of the bacterium is antibiotic resistant or not and a host of other diseases as well.
Since COVID-19, we have all become more skilled at performing scientific testing, but it does depend on a quality sample and a quality test. Believe it or not, the ‘home test’ for foulbrood is quite similar. There exist tests that can be purchased to definitively diagnose either of these diseases – it is possible to get a false negative. That said, they are not readily available nearby…so I ordered one of each from Amazon (fast, free shipping) and then did some more RESEARCH.
There exists a home test for AFB that utilizes diluted milk and some dead larval samples. The directions are not too complicated. This video by Randy Oliver explains what you need by way of a sample, materials and how to read the results.
We performed this test and the results were negative for AFB…a bit of a relief, with the caveat that the chance for human error in sample selection is high. So we do need to confirm these results another way.
Holst milk test: Sample on the right, control with only dilute milk on the left. There is a slight discoloration from adding the larvae, but the solution did NOT become clear which would indicate AFB.
A bad photo (sorry) of a diseased brood removed from a cell.
Disease brood (circled in blue).
So we are confident we have EFB and not AFB because:
- We saw symptoms consistent with the former. We also didn’t see many characteristic AFB symptoms: we didn’t see roping, didn’t have a smell, didn’t see lots of sunken caps. Some of the hives (not at Whiting but personal hives) were overcoming the weak hive component.
- Dan Keane, our mentor and a trusted hive-mind, agreed and confirmed EFB.
- Hoist milk test was negative for AFB.
- The rapid tests were positive for EFB and negative for AFB (our smoking gun).
Treatment for the two are different. If the situation were American Foulbrood, we would have chosen to euthanize the hive. Because the diagnoses is European Foulbrood, we are choosing some of the following treatment options:
- Simulate a nectar flow. Although the real nectar flow is on this season, because the hives are weak we are choosing to feed them. We are feeding in a manner to minimize robbing risk, too. In the absence of abundant foraging field bees we want to feed our bees!
- Be very aware of sanitization from hive-to-hive and beeyard to beeyard. Disinfecting and switching tools, wearing gloves, being aware of steering wheel in car, etc.
- Treating with antibiotics. This is a little more difficult to do, as a veterinarian needs to prescribe. Please check with your local vet or extension office to determine the best way to proceed with obtaining these.
- Doing a shook swarm. It’s possible to shake all the adult bees from the sick grubs and contaminated equipment into a fresh hive. This is often done after an antibiotic treatment, because the adult bees that have been medicated and can hopefully work to rebuild the colony in the absence of abundant contamination.
- In the case of a strong hive that seems to “outgrow” it, we would choose to allow the hive to continue. Close that bee yard to influx from other locations. Evaluate next spring. If we see any symptoms or indicators that it has survived to the next season, we shall do a shook swarm on all hives at that location.
There are lots of cogs in this wheel. We had purchase 8 nucs from this supplier and located them at 4 different locations. They are at Whiting, each of our personal apiary locations, and fourthly at a friend’s operation. All 8 of these nucs are seeing symptoms of EFB, along with other nucs from the same supplier at entirely different locations purchased by another beekeeper. Management decisions are different, a combination of the above, for each of these unique circumstances.
For Whiting, which when it comes down to it is what this blog is about:
- We fed the hive to nourish the bees. This colony is very weak, and never grew past 5 frames.
- Being aware of sanitation working this hive (of course!)
- Treating with antibiotics. On recommendation of our mentor Dan and because we were able to procure the drugs, we choose to treat a 3- dose course of antibiotics.
- Doing a shook swarm. We are scrapping all frames, disinfecting all equipment and starting this hive fresh in a new box. This is coming up quickly, so expect a blog article in the upcoming days on why we are choosing this method for the Whiting hive (and not all the other circumstance with same diagnosis) and the procedure that we are doing.
All-in-all it has been a stressful month. Yes, month. Around one month ago Debbie first notice symptoms in her personal apiary that concerned her. After lots of research, diagnostics, conversations with our hive-mind, calls to the supplier… we are on the road to recovery. The above steps are the choices we are making at Whiting. But trust us, for the 7 other hive with the same diagnosis that are under our care, similar consideration has led us to different choices in management.