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  • Advice regarding CPBV please

  • Honeybee pests and diseases.
Honeybee pests and diseases.
 #10753  by Jules59
 04 May 2021, 12:35
I have a small apiary at the end of my garden with 3 WBC hives and been beekeeping for just 3 years.
All 3 were productive colonies last year, survived through the winter well, expanded rapidly this spring and have double brood boxes. All colonies received clean hives this spring (bleached and scorched where appropriate)
One colony (the biggest) has since developed CBPV with typical signs: a pile of smelly rotting bees out the front, hairless and shaking bees, K-wing sign.
So far the Q seems unaffected with 13 frames of brood (BIAS) and no signs of swarming.
I have no out-apiary but have moved and rotated the affected colony to reduce cross -contamination through drifting as much as possible.
I have no personal experience of CBPV. So I wonder what to do now?
Advice so far obtained is variable (nothing new there :D )
Active destruction of the colony seems a bit drastic to me at the moment.
My thoughts are to tough-it-out for now as the weather is awful. But when its warmer carry out a bee dump and allow the healthy bees to get back to the Q residing in a clean hive but with the original frames.
I'd appreciate any comments regarding my plan and any additional advice.
 #10754  by Patrick
 04 May 2021, 13:39
Hi Jules

I had a significant single case of CPBV a couple of years ago, with all the classic symptoms. In the absence of knowing a positive intervention, I left them be. Its supposed to be a common latent issue which comes out due to stress and spread by overcrowding (not in my case) / and sometimes advised to requeen (which in itself may be a stressor).

A couple of weeks later the affected bees had died outside the hive and the remainder carried on okay. it has not re-occured. Maybe I got lucky, but I would just cross fingers for better weather.
 #10760  by AdamD
 04 May 2021, 19:10
I have a colony with it now, although it's expanding OK and the number of dying bees is already reducing. The colony isn't that big yet - but none are as they are way behind normal years. What I am doing with this one is to move the bees onto clean comb with a bailey comb exchange (1 week in) and I have also fed it strong thymol syrup to help ensure it's nosema free. The idea that I am trying to help the bees rid themselves of the CBP virus as best as I can. (The comb, to be fair, is as dark as anything so it really does need changing out!). I don't know if my intervention will help much; I have had colonies with it before and left them to it and the problem tends to go away after time. I am concious of ensuring that I don't spread disease fromone colony to another - so it's the last one I inspect and I have a container of bleach/washing soda/water and a brush that I use to clean my hive tool and smoker with between inspections.
 #10779  by MickBBKA
 07 May 2021, 00:48
The only remedy that may work is to give them double the space they have. Unfortunately the weather we are having at the moment is the perfect conditions for spreading this bee covid. We have just had another 4 nights below -1c and its been 7c during the day so the bees are all stuck inside in a cluster spreading bee covid. If it ever warms up the sick bees can fly out and die or get lost outside and the ones that get back will be refused entry by the guard bees. If you have reached the point of no return with masses of infected bees in the colony then cage the queen and take the rest of them and dump them well away from the hive. Put the queen back and let the healthy bees return to her, make sure they have enough stores to get by. I had a colony like this last year that went on to produce 140lbs of honey, I also had one about 5 years ago that went from double brood and 4 supers to 2 frames of bees that just gave up and died. Genetics probably have quite a lot to do with their chances of pulling through.
AdamD's suggestion of comb change is well worth considering but I would add a few caveats. Is the colony strong enough to do a comb change ? I don't think CBPV is spore forming but requires bee to bee transmission so the comb may not carry this infection. Does old comb actually help reduce it because of the build up of propolis ? Have you treated for Varroa which is probably a vector for this virus ? Just my thoughts no science or biology involved.....
 #10783  by AdamD
 07 May 2021, 10:02
Good points Mick. I have not done the drastic thing you have. A comb change may not make a significant change at all - although it will tend to spread the bees out a little which should help with CBPV.
I'm not quite as cold as you but the wind off the N Sea is certainly present here! Sunday looks good though for temperature.
With regard to genetics, I have done experiments with chalk brood where the CB moves with the queen, so queen genetics is significant in that disease. I am not aware of any real work done as to whether re-queening really works as CBPV can go by it's own accord, it seems.
 #11017  by AdamD
 28 May 2021, 12:28
As a continuation of my CBPV colony, I have moved the bees onto new comb, using a Bailey Comb Exchange. Interestingly enough, after 3 weeks, the lower box had some random open drone brood as well as a fair amount of sealed drone brood scattered about, whilst in the upper brood brood box where the queen is, it had worker brood only. It also had nearly no stores at all as the older bees are dying before they can do sufficient foraging. So is there a laying worker perhaps? Or worker policing is not doing it's job? Shaking the bees off the manky drone brood onto a board in front of the hive, quite a few of these bees didn't make it back to the colony which makes me think they had CBPV themselves and had yet to be chucked out.

If colonies with CBPV can recover and it seems that the queen doesn't get the virus herself, and it doesn't transmit to neighbouring colonies just 3 feet to either side by drifting, which is my experience, would we conclude that it's a largely genetic condition in the workers, like Chalk Brood?

To this end, I have put in a protected supercedure q/c from the neighbouring hive. The queen has been caged for now and I'll remove her shortly. I'll see if I can institute a supercedure in this stock.

The neighbouring hive had one open and one sealed queencell and a couple that had been noted a few days before and have been broken down from the back. (The queen is not going without a fight!). The queen was being aggresively nibbled and pushed around, although still laying - albeit slowly with just 5 frames of brood. I've read about but not seen such overt behaviour towards a queen before and cannot see that she will remain in the hive for much longer! Maybe once the queencell is sealed she will be gone?