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Chronic Bee Paralysis Virus: Signs and Symptoms - Practical Guidance

The visible face of Chronic Bee Paralysis Virus - Black, hairless bees that look greasy in bright light

I have a sad story of one of my colonies which has suddenly become infected with CBPV, Chronic Bee Paralysis Virus and it seems there’s not a great deal to be done for them.

I’ve checked out quite a lot of scientific research and although there is plenty of research out there identifying CBPV there doesn’t appear to be a great deal of practical help for beekeepers in how to help your bees survive the infection.

Here’s what I found out and what I intend to do with this colony.

CBPV or Chronic Bee Paralysis Virus is one of around a dozen different viruses that can affect a honeybee colony, it’s known as a single strand RNA virus and just seems to pop up in colonies with no apparent obvious route of infection.

It seems viral infections of honeybees are probably the least understood of all the honeybee diseases but CBPV is both infectious and contagious, which basically means it's easy for the individual bees to catch it and easy for them to pass it on to other bees! Once it takes hold it just seems to spread throughout the hive ultimately causing the collapse and death of the colony.

The first opportunity we as beekeepers get to see that something is wrong could well be the end stage of the infection when many bees are dying and drop onto the ground outside the hive in what can be mistaken as a poisoning event, especially if you are near farmland and see the farmers spraying their crops, well, it’s not always down to the farmers as we will see.

Dead and dying bees on the ground outside the hive

CBPV has two types or syndromes described which give very obvious visual clues as to what is going on.

Type 1 syndrome is seen when the honeybees start shaking or trembling their wings or bodies, not to be confused with a waggle dance, once you’ve seen it you can tell the difference straight away. Difficult to show in a blog post but check out my video on my patreon page or YouTube.

Type 2 syndrome is the one where the bees become hairless, they look darker than normal and if you have dark bees already they take on an almost black appearance. If you catch the light on them they look shiny almost greasy or wet looking.

Once you spot the CBPV signs it's easy to see infected bees

Some of the research papers I’ve read while researching for this podcast suggest that if you watch the bees closely you will see healthy workers nibbling at the sickly bees, I’ve not stopped long enough to observe this but while I was filming our video I spotted it and managed to capture it on film. The result is a pile of dead bees on the ground outside the hive within a few days and the colony is lost within a few short weeks.

In terms of transmission between bees it appears that the scientific community have currently no exact answer but do know that bees in confined spaces pass the virus to each other, so at this time of year when colonies are growing to their largest populations in confined hives there is a greater chance sickly bees will rub against healthy bees and pass it on.

A bit like a flu virus on the London underground at rush hour! No escape for anyone standing next to that coughing and sneezing chap standing by the doors! You just know that within a few days you’re going to have the symptoms!

Given that the bees in confinement seem to spread the disease most quickly I was tempted to split the colony but would that just propagate the problem, I’m really not sure. They certainly have what I would call , enough room, a couple of supers on to allow them to expand so I don’t think it is being confined in a tight space more something to do with their daily communal activities and that’s really worrying.

So the bad news currently for beekeepers, is that once the visual signs are apparent it’s almost too late to do anything about it.

I know it’s not easy to describe in a blog post what to look out for, but hopefully the video showing how that colony looks and what the symptoms look like in individual honeybees will help, so look out for that and hopefully my misfortune will allow you to see what the disease looks like.

There is also evidence to suggest that the virus is found in the bees faeces, and as the workers go about their cleaning duties within the hive they are also picking up the virus through this route, so a dirty hive is likely to more easily spread the infection. Another reason why you should maintain good hygiene and keep your hives as clean as possible. In this instance I had performed a Spring clean on this colony so I had replaced the floor, brood box and crown board in May so there wasn’t likely to be any affected material left in the colony. The virus multiplies to incredible numbers though, so a single bee can be victim of many millions of viral strands, if that’s the right way to describe them! It seems to develop all over the place internally for our bees so once they have the virus there’s not much chance of them individually surviving.

The infection popped up last Autumn in one colony and it caused that hive to die out, there had been no previous CBPV in that apiary so I have no idea where it came from, I removed the colony quickly from the apiary and cleaned it out by scrapping and scorching the hive and boiling the frames, all the wax was rendered down. I’m assuming that would be enough to kill the virus but I’m not sure, more research on my part required

Just one Type 2 Syndrome worker on this frame but they were all shaking with Type 1 Syndrome, not good!

All of my hives are kept in staggered rows, entrances facing different ways with plenty of room between them so drifting shouldn’t be a problem, my thoughts turned to maybe drones moving it between colonies but I have no scientific evidence of this.

I’m a pretty clean beekeeper too! I wash my hive tools between individual colony inspections and wash my gloves at the same time, disposing of them at the end of the apiary inspection, but if a single infected bee can contain many millions of virus particles and I happen to have accidentally crushed one with my hive tool and then forgotten to wash it before the next hive maybe I did move it across, it’s quite worrying really.

There are beekeepers out there with vastly more experience than me who never wash their hive tools between hive inspections and swear it doesn’t matter, I for one will continue to wash and reduce the perceived risk as I see it.

The scientific community is not ignoring the problem, Giles Budge from Newcastle University here in the UK has set up a consortium of scientists and bee professionals to study the disease, why is it scientists always use such grand words, for consortium replace with group, maybe it helps raise more funding cash who knows!

Anyway, it’s good news as there is now a group of people looking specifically at Chronic Bee Paralysis Virus. What we really need is some help in answering the question of what can the practical backyard and commercial beekeeper do to help their bees fight off this infection. The CBPV consortium is looking for help, if you have the characteristic behaviour or symptoms in you hive they would love to hear from you.

Maybe I’ll be able to visit them and discuss some of their work for the podcast at some point in the future.

For now, I’m going to continue to check up on this sickly colony and do my best to prevent it spreading to my other colonies, I don’t have an isolation apiary available to move the hive away so we will have to sit tight and wait it out.

If you’ve experienced CBPV and can offer some insight please do get in touch it would be great to hear from you.

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Hi Stewart,

Thanks for your informative posts and video! A friend has CBPV in a strong colony at the moment with many dead bees and I hadn't given the topic any though for some years. Although I have seen some symptomatic bees here and there in my colonies over the last 11 years of beekeeping, I have never experienced the huge numbers of dead bees outside the hive and I suspect there is probably a genetic element making bees more or less susceptible as there is with some other bee problems. Having had a good think and a chat with my friend, I am suggesting a shook swarm into a clean hive with new frames and feeding and requeening fro…

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