Chronic bee paralysis virus

Honey bees that appear black, hairless, and shiny may be infected with Chronic Bee Paralysis Virus (CBPV). The symptoms of this virus appear only in adult bees and include the loss of body hair, trembling, and the inability to fly.

Affected bees are often described as “greasy” in appearance and are frequently seen near the hive entrance or clinging to blades of grass in the immediate vicinity of the hive. Their paralyzed wings are often held at an unusual angle that resembles the letter “K.”

Because the healthy workers in a colony will quickly get rid of the infected bees, Chronic Bee Paralysis Virus rarely takes out a whole colony and is considered only a “minor” honey bee disease. However, if you find large numbers of such bees, the colony can be fortified by supplementing the population with brood from another colony. Usually, an infected hive will recover on its own.

Because some research has shown that susceptibility to the disease may have a genetic component, re-queening a hive may be necessary to prevent future outbreaks.

In my own experience, I have seen these symptoms only twice. Both times I found three or four distinctly greasy-looking bees walking around on the top bars with their wings splayed out. I removed these individuals and never noticed any further evidence of disease.

Don’t panic if you see symptoms of the disease, but stay alert. If the incidence of infected bees seems to increase, consider re-queening. As with most viral diseases, there is no cure for CBPV.


Discover more from Honey Bee Suite

Subscribe to get the latest posts to your email.


  • I have noticed greasy-looking black bees in some of my hives during the winter. I am highly suspecting CBPV, which is also associated with confinement. They leave dark feces in the hive as if infected with nosema but have repeatedly tested nosema-free. It usually shows up in colonies not treated for mites as the colony is weakening in the winter and the population is dropping. It is gross to open a hive on a warmer winter day and see disoriented very greasy bees moping around unable to cluster, and severe defecation blackening parts of the comb or top bars. The infected colonies rarely make it through the winter. Other hives not treated for mites show no symptoms all winter, but I have had bees to come down with it if I move frames of leftover honey from a dead-out to another hive that is low on food supplies. It seems quite contagious. Does anyone know if the virus can live long-term in honey? I have never noticed the trembling at all, and have never seen it during the summer. I treat the badly stained frames by cutting out the wax, scraping the wooden parts, installing new foundation, and letting them set out in the sunlight. Will a bleach solution kill CBPV? (Some viruses are killed by UV light and dehydration, but I do not know if this is true of CBPV.) I live in West Virginia, US.
    Found this link interesting: http://www.ibra.org.uk/articles/Chronic-bee-paralysis-virus-infection-in-honey-bees-Apis-mellifera-L
    (Click on the “open access” link for the full text PDF)

    • Michael,

      Interesting article. Like I said in my post, I’ve only seen what looked like CBPV twice and in neither case did I have it tested–so I don’t really know. Both times were in late fall or early winter, and in both cases the greasy bees were away from the cluster, meandering around the top bars. The cluster had probably rejected them.

      It was scary looking. At first I wasn’t even sure they were bees because their appearance was so altered. But I never saw the disease progress as you describe; I just removed those bees and that was the end of it. If I ever see it again, I will send them in for testing.

      In answer to your question, I have no clue how to disinfect for the disease, or if the virus can live outside the host.

  • I think my two hives have CBPV and have lost almost 90% of both hive populations. What do I need to do. Do I burn the hives? Wait out the process and see if the hive survives? Any advise . This all started 7 days ago

    • Michael,

      I don’t have an answer for you. I’ve never heard of burning hives with CBPV. Usually only a small percentage of the bees show symptoms and it doesn’t kill the colonies. I’ve only ever seen a few bees have it; those bees died but the hive lived on. Seven days isn’t much time for a 90% infection. I’ve heard of really bad infections but they are rare, and I certainly have never seen one. I’ve been told it is one of those diseases that is always around but never becomes much of a problem. I really don’t know more than that. Have you called your local extension agent? Maybe they know of outbreaks in your area and what to do about them.

      • I met with a professor from OSU yesterday and took him samples of the bees along with photos I took he said it sounds and looks like my hives got poisoned. He will be running test for tracheal mites, Cbpv and veromos (sp). I have bee samples being tested for poisons with the state of Oregon agriculture pesticide division. I should know more soon

        • Michael,

          Let me know what you find out. I should have thought of pesticide poisoning because it happened in such a short period of time. Makes sense. Too bad about your bees, though.

  • You mention bees clinging to blades of grass but isn’t it normal to have some bees in the grass that are too old and tatered to fly? For instance, I have 5 hives and a very small back yard, I have to be extra careful walking barefoot in the grass. There is probably one bees per square yard. Yes they have worn wings and some have wings that don’t fold together normally. Is this normal or reason to be concerned?

    • Wil,

      Sure it’s normal to have bees in the grass, but when you can no longer see the grass, that is not normal.

      Also, I say in the post, “Affected bees are often described as “greasy” in appearance and are frequently seen near the hive entrance or clinging to blades of grass in the immediate vicinity of the hive. Their paralyzed wings are often held at an unusual angle that resembles the letter “K.”

      Many greasy bees holding their wings in a “K” is different than a few tattered old bees with worn wings that otherwise appear normal.

    • David,

      That is true, but they don’t look the same. Fighting bees look black and hairless, but CBPV bees look like someone coated them with motor oil.

    • It can be hard to tell because, workers will bite at the hairless infected bees at the front entrance to kick them out of the hive which make both the bees and the behavior mimic a robbing scenario. Look for the ALL black bees, I like to put a white mat in front of the hive to see losses and the K-winged black bees.

  • Hello Rusty,

    Something like the chronic paralysis virus happened in one of my hives. I just went inside it today to see what the damage is and I found out that there is no brood, so I guess the girls are on top of that queenless (maybe the thousands of disoriented bees around the hive are just a sign of queenlessness?). There are still few thousands bees tending to their supplies – a lot of full honey frames, they were still not completely robbed.

    My question is – is it still worth it to requeen, we have still at least a month or so of nice weather here in North California. Would they be able to make it, or would she die of the same virus herself as well?

    Sorry, this is my first year and first disaster so I am trying to save the day. Thanks, Jitka

    • Jitka,

      Have you looked for the queen or are you just assuming she is gone? Colonies often have very little or no brood this time of year, so I would not jump to conclusions. Remember, the bees are actively lowering the population in preparation for winter, they are not trying to increase it.

      Also, you say there are thousands of disoriented bees around you hive. What do you mean? Are they outside doing orientation flights? If so, that is a good thing. Or are they on the ground writing and dying?

      And why do you assume chronic bee paralysis? Do you see lots of bees in that condition?

      You say this is your first disaster, but what you are describing sounds pretty normal to me. If you could answer these questions, maybe I would get a better picture.

  • Hello Rusty,

    Yes I did look for the queen and she was not there. And there was no brood whatsoever, only a few half emerged dying bees. Now the hive is completely dead anyways so that was it.

    By disoriented I meant crawling on the ground within 2 yards from the hive, not able to fly, being bullied by a few wasps and eventually dying. I did not see any other specific condition but since it was not sudden – this was slowly happening over the last 3 weeks, number of dead bees on the ground increasing – we ruled out poisoning. So I was looking for other diseases and came across this one that seemed to fit the bill the best. I am planning to send a sample to USDA for testing, just to know what happened.

    Thanks for your time and help, Jitka

    • Jitka,

      I still wouldn’t suspect chronic bee paralyses virus, but perhaps tracheal mites, although it seems the wrong season. Let us know what you find out. I would really like to know.

  • Sure, will do. Actually the tracheal mites were my first guess but in some other beekeeping forum they told me that that disease ‘does not exist’ any more in USA so i crossed it out. As I said, I am a first timer and have to rely heavily on what other more experienced people tell me 🙂

    • Jitka,

      Tracheal mites took a dive because of Varroa mite treatments, but some places are reporting a comeback of tracheal mites in the last couple of years. It is believed that some strains have developed resistance to the varroa mite treatments. Although it it probably unlikely to be tracheal mites, I definitely don’t think it’s impossible. Tracheal mites do exist in the USA.

  • I have one hive confirmed CBPV and Lake Sinai Virus 1. Despite these viruses, with its current population and stores, I doubt it would make it through the winter. I had planned to combine with another hive but with these confirmed diagnoses have decided not to. But now I don’t know my options. Try to nurse it through the winter and requeen in the spring? Destroy the bees and current brood comb? There is a deep of fully drawn but empty comb. Can I use it in a nuc next year? I’d hate to lose all the comb as well as the bees.

    • Dan,

      I need to double check on this, but I don’t believe these viruses can survive outside of the host bee, so the drawn comb will be fine. As for the bees, these viruses by themselves usually don’t take down the entire colony. The bees may be able to be nursed through it. You just have to decide whether it’s worth it to you.

  • I am a new beekeeper in Ohio and I went into my hive today and saw something that I am not sure what it is. I have 3 medium boxes and I use a top feeder. I have been feeding sugar syrup and right in the middle of my 2nd box there is a 3 inch wide section from the top of the frame to the bottom of the frame of what looks like maple syrup and dead black bees attached to the comb. There is no foul smell, but I don’t have any brood and cannot seem to locate my queen. Any thoughts?

    • Denise,

      Nothing occurs to me. That you don’t have any brood is typical for November. And since she’s not laying right now, the queen may just be running around and hard to find. But the strip is weird. Are the dead bees in the syrupy stuff? That could make them look black. How about small hive beetles? Do you have any? Are you sure the comb wasn’t scraped against something? How about the comb opposite the strip? Does it look weird too? Are the cells broken or is the syrup on top of capped cells? Do you have a photo?

  • Hi Rusty,

    I have never encountered this issue in my hives until recently. My strongest hive has been exhibiting this disease for a month. In discussing this with another fellow beeker he stated he has a hive that has it but has seemed to improve and is basically back to normal. For my hive this isn’t the case, I checked them yesterday and there are at least 300 more dead bees on the ground and multiple bees shaking on the landing board. I did treat with MAQs the month before as there was a high mite count. I am at a loss as to what to do, but I don’t think this hive is going to improve and it feels inhumane to let them suffer. I have moved my other hives to my new house and not sure what to do with this one. Any advice? Perplexed and sad.

    • Lara,

      It’s hard to diagnose CBPV, but if you’re sure that’s the problem, I probably would not move that hive along with the rest because you certainly don’t want to spread it. Is there any way you can leave them where they are or do you have to do something?

      • We sold our house so it has to be moved. The hive is exhibiting greasy, shaking and k pattern wings. It started out as 1 or 2 bees, but the virus has taken hold. Hundreds of dead on the ground and others shaking on the front. I have cleaned up the dead to be able to see a new amount and its staggering. I just fell its inhumane to let it continue and it could be spreading to native bees. Very sad beekeeper ?

        • Lara,

          You could kill the colony with soapy water or pesticide. It might go a long way to preventing the spread and ending the prolonged misery.

  • Hi Rusty,

    So what are your thoughts on this since the beginning of this forum? I am experiencing the same issue, I moved the hive away from my other hives and just riding it out now, just noticed something was weird about a month ago, what can be done? I did put them in a very sunny hot location and changes to a screen bottom board and it seems to have made a slight difference, could just be wishful thinking. I can’t find any info on CBPV at all. Thanks for any info

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.