Feeling Helpless About Surging Chronic Virus

Frightening Bee Virus Is Aptly Named

A bee infected with CBPV
A bee infected with CBPV (crown copyright – National Bee Unit)

Recent Reader Poll

Thank you to those kind readers who responded to my poll about the greatest challenges facing you as beekeepers. The issues of swarming and failed/missing queens topped the poll, but for a long time, the leader was Chronic Bee Paralysis Virus (CBPV), which ended up in third place. This affliction of honey bees can be devastating (but not always), is definitely on the rise, and we don’t really know what to do about it.

Extract From Interviews with Beekeepers

One of the bee farmers who talked to me about CBPV, back in 2018, was Peter Little of Exmoor Bees and Beehives. We very much need the research work being performed by scientists (Giles Budge and David Evans spring to mind) but real life anecdotal experience can also help to paint a picture. The following is a slightly edited extract from my book.

Peter: Chronic Bee Paralysis Virus, Deformed Wing Virus…you didn’t have these worries all those years ago. You had acarine and nosema, and maybe a bit of chalk brood, and that was it. Now it seems there are many other issues. CBPV is one of the big ones, there’s a real problem with it throughout the country, and that’s why Giles Budge (Newcastle) and David Evans (St Andrews) have got the funding through the NBU, to do research on it. I’ve got one of the testing kits which they sent to me, so I can send any bees that I have with CBPV to them. It’s been wiping out colonies big time. Some people have had 40 or 50 colonies in an apiary wiped out with it. It’s been wiping out 50% of some bee farmers’ stocks.

“Steve: I thought it was because they had too heavy a varroa load.

Peter: No, CBPV is not varroa related. They think now that this was what acarine was in the past, not the tracheal mite, but the virus. Over the last 4–5 years, it’s been getting worse and worse. It makes no sense. I had an apiary last year with 35 hives and one colony got it. It comes suddenly – at first you think you’ve got a spray poisoning incident, you’ve got dead bees all round the front, but not over a big area, just under the entrance. They can be 2–3 inches deep, with dead bees, yet a week earlier there wasn’t a problem. All of a sudden, you have piles of dead bees and bees trembling, shaking. They aren’t black and shiny or anything, just normal bees, but shaking.

Steve: What about the black, shiny ones? 

Peter: It’s a paralysis, but this one they don’t have to be shiny black. You will get hairless bees in there. They look shiny because they are hairless, the other bees have been nibbling at them, but they are not black, just shiny. The queen might be laying like mad, and they’ll supersede her, and then she’ll die, and that’s the end of them, unless you re-queen, but then she’ll die. Or the virgin will mate, and she’ll be superseded again. They keep dying and dying. You’d have to feed them. You can have a hive in the middle of an apiary that gets it. It goes on for 3 months, stinks to high heaven – you have to spade away the dead bees every week. They dwindle to half the size, then all of a sudden, it stops! No more dead bees, just like it’s been switched off. They start collecting honey again, they build up and if you’re lucky, they may get strong enough to over winter, and they may never get it again. You don’t see a sign of it in that colony again ever. 

Peter Little and Steve Donohoe
Peter Little and Steve Donohoe

In another colony, it goes on and on and on, and then they die out completely. I had an apiary with 16 hives, and it started in the strongest one, and they dwindled and dwindled, and all 16 hives got it – every single hive. This went on for three months. All the hives survived, apart from that first one. I moved that miles away to somewhere remote, and they died. One of the colonies went down to 2 frames of bees which I put in a nuc with a virgin, and I moved them away, but they lived, and I’ve still got them.

All the other hives got over it, the other 14. It stopped like the day it started, and most of them produced quite a bit of heather honey, strangely. Why is it that you can have one hive get it out of 35 and none of the others get it, even a hive six inches away, and then in another apiary they all get it – every hive. It makes no sense.

You get the shiny bees, they get over it quicker. In the other type the bees don’t look any different whatsoever, they are not shiny, just lethargic. They just fall out of the entrance and lie on the ground with their legs in the air, and they just die. That’s the one that normally kills the colony. Occasionally, they get a touch of both of them and generally get over it. 

David Evans is a virologist who worked at the University of Warwick, and I got to know him because we were making hives for them for five years or so. They were getting bees from Colonsay, black bees from Andrew Abrahams, and they were doing research on them into varroa related viruses, comparing bees that had varroa with others that had never had it. David has moved now to St Andrews in Scotland. He’s also a beekeeper and has plenty of hives. David and Giles Budge have now got funding to research the cause and transfer, and hopefully the cure, for Chronic Bee Paralysis Virus. They haven’t told me how much, but the word is “substantial funding” to do about five years of research. They’ve sent out the kits to people that they have dealt with previously.

I read up a lot on how long a virus can live outside its host because I thought they would die straight away, but apparently not. They can live on work surfaces and so on for some time outside the host. The reason these guys have got the funding is that there is so little known about it. It’s such a serious problem, but there is very little known about it, so thank the Lord for people like Professor David Evans and Giles Budge. I think it’s fantastic that they’ve got the funding.

Steve: Yeah, definitely. 

Peter: It makes you feel helpless, an issue like this, there’s nothing you can do. We can get rid of varroa mites, we know what to do with those, Steve, but when you’ve got something that’s invisible and your bees are dying. There’s nothing you can do about it, you feel terrible. We have to send them samples; some recently dead, some older ones, some samples of bee poo, you name it. We have all these little tubes to put it in and have to label it properly with dates, and complete a massive questionnaire. It’s all to help with this research.

Research Findings

This isn’t a new disease, Aristotle referred to it quite a few years ago https://theapiarist.org/aristotles-hairless-black-thieves/. I was very cheeky and contacted David Evans recently, to ask him to read my shabby article and point out any errors (there were plenty). He’s a busy guy, so I’m extremely grateful for his help. He told me that they are preparing the final publication of their findings. “We’ve not got a cure, but we didn’t set out to find one (and wouldn’t have been funded had we claimed that was what we were aiming for). However, I think we have a much better idea of where the virus is, where it lurks when there is no overt disease and – at least potentially – why disease suddenly flairs up in some hives, particularly strong ones,” said he.

Research by Giles Budge, David Evans et al. published in 2020 https://www.nature.com/articles/s41467-020-15919-0shows the following:

  • cases of CBPV rose exponentially from 2007 to 2017
  • clusters of the disease pop up in different areas each year, so it can be bad in an area this year but gone the next
  • beekeepers who imported queens within 2 years had a 1.8x higher chance of having the disease than those who did not
  • commercial bee famers had a 1.5x higher chance of having the disease than amateurs

The importation issue could imply that foreign bees are bringing it in and infecting our bees; many will claim this. However, it could be the opposite; that imported queens have no disease, and they catch it from UK bees and succumb because they have no immunity. David told me that the CBPV in European bees is very similar to the virus in UK bees, so it’s unlikely that the problem with imported bees is related to different strains of virus.

It does seem apparent that the virus is being spread by the movement of bees, whether it is the importation from other countries or moving bees from place to place as part of commercial honey farming. This should not be a surprise; we have seen with the COVID-19 pandemic how efficiently viruses can spread and mutate.

More Anecdote

A bee farmer friend of mine told me that he moved bees from the same place to two separate sites on the same farm. The same bees from the same place were split into two groups on the same farm. One group became afflicted with CBPV, whereas the other did not. The CBPV bees quickly dwindled, so my friend moved them away, and they recovered. Another bee farmer in the area had the same situation, except that he did not move his sick bees away – they all died.

I have no idea what the above scenarios tell us. It’s possible that moving the sick bees took them to an area with better available nutrition (sources of pollen). Perhaps moving the living bees away from the piles of dead bees was what helped. Who knows? It doesn’t explain why one group showed no signs of the virus, and the other became very sick.

Removing The Floor

One approach being tried by beekeepers stems from trying to reduce the spread of the virus within a colony. One source of disease spread is dead bees on the floor, which are riddled with virus. By removing the floor altogether the dead/dying bees can drop to the ground. This, combined with ensuring that there is plenty of space, may help to reduce transmission, and give them a better chance. The base of the bottom box needs to be well clear of the ground for this to be worth it. On the downside, it’s an invitation to robbers.

I have lost colonies to CBPV, but so far, it has only been the occasional, isolated incident. It would be terrible to see a whole apiary fall down. To me, it seems to strike when big colonies are confined to the hive during prolonged bad weather. David confirmed that there’s a well established connection between strong colonies, CBPV and confinement; it’s something that Giles Budge has spent a long time investigating. I’m not keen on removing floors because of the risks of robbing and consequential disease spread.

What do you think?

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