# Deformed wing virus is a recent global epidemic in honeybees driven Varroa



## JWChesnut (Jul 31, 2013)

This paper demonstrates that DWV became lethal to Apis mellifera after it encountered Varroa. The epidemic bee deaths caused by DWV are part of the uncontrolled expansion of Varroa into Apis mellifera, and not an inheritance from Apis cerana. DWV has mutated toward lethality and ease of infection from a non-lethal prior genotype.

http://science.sciencemag.org/content/sci/351/6273/594.full.pdf


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## JohnBruceLeonard (Jul 7, 2015)

A very interesting article. Thank you for passing it on, JWChesnut.

John


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## Fergus (Jan 27, 2015)

I guess my question at this point given this information is... Now what?


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## Oldtimer (Jul 4, 2010)

Thanks for that.

Something I've noticed about DWV, this is just purely my own observation so just anecdotal, is that years ago hives with severe DWV had large numbers of bees with shrivelled wings, a badly infested hive was obvious. Now, not so much, DWV seems to have morphed into more of a brood disease. IE, the brood can be in a bad state of PMS but the adult bees show a much lower percentage of bees with shrivelled wings than would have been the case 10 years ago for a comparable level of PMS. 

The adult bees will be sickly and lacklustre looking but fewer displaying the standard shrivelled wings.

Of course this is in NZ so don't know if it's the same in the US. I'm going to post on my local forum also to see if anyone has noticed this.


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## maudbid (Jul 21, 2014)

"Now what?"

From this popular press article:

"We must now maintain strict limits on the movement of bees, whether they are known to carry Varroa or not. It's also really important that beekeepers at all levels take steps to control Varroa in their hives, as this viral disease can also affect wild pollinators," Wilfert said.


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## RayMarler (Jun 18, 2008)

Oldtimer said:


> Thanks for that.
> 
> Something I've noticed about DWV, this is just purely my own observation so just anecdotal, is that years ago hives with severe DWV had large numbers of bees with shrivelled wings, a badly infested hive was obvious. Now, not so much, DWV seems to have morphed into more of a brood disease. IE, the brood can be in a bad state of PMS but the adult bees show a much lower percentage of bees with shrivelled wings than would have been the case 10 years ago for a comparable level of PMS.
> 
> ...


Yes Oldtimer, I've been noticing the same thing here over the last 3-4 years. JRG13 has also I think, as he has posted in another thread about it. We are both in California, I'm not sure if beeks anywhere else has noticed it or not.


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## Oldtimer (Jul 4, 2010)

Thanks Ray now I know I'm not the only one!

I searched for JRG13's thread but no luck, maybe he'll chime in. I posted this on our local NZ forum today also, and one guy suggested it might not be that DWV is doing less wing damage, but because there are more new mite vectored pathogens appearing on the scene all the time, that could be adding to PMS but not doing the wing damage. Sounds plausible.


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## RayMarler (Jun 18, 2008)

Oldtimer...

From this thread...
http://www.beesource.com/forums/showthread.php?320334-Dee-Lusby&p=1366297#post1366297

I've never seen any hive recover here. I don't see a huge influx of DWV, what we see is severe PMS and dwindling of hives to below viable thresholds in August-September. Not to say I don't see an increase in DWV as mites build up, but it manifests more into just plain dead brood, not bees with deformed wings. If you try to prop them up now, the cold in November-December finishes them off. Not to say you can't have a few dinks that survive, but they will always need a frame of brood and bees come spring to make it, and they never show any improvement year to year, basically, I know they'll just be crashing again due to mites come fall again which makes sense on a genetic level if they haven't requeened themselves. Recovery instances can be explained though in a shift of genetic make up in the worker population due to different drone donors, just that I've never seen it. I had a few promising hives this year, which I left treatment free, it was a mistake I came to find out Monday as all were empty boxes. Some would claim that I weeded out the crap, but this is untrue, they were markedly better than most of the other bees I had, they were able to go into late fall with decent populations and stores while the truly susceptible lines were dead months before, but because I didn't help prop them up a little so I could improve upon the line, I no longer have them to work with, and now I've lost some of the diversity I was gaining in screening all the different genetics I've been looking at. That being said, I couldn't be more happier in seeing TF folks succeeding, it's just the blind chest beating about how it's the absolute way to keep bees that just shows blind ignorance of the whole picture at hand.


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## Oldtimer (Jul 4, 2010)

Oh thanks Ray, very kind of you to hunt that down. 

What he is saying is my own more recent experience exactly!


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## RayMarler (Jun 18, 2008)

Yes, like I said, me too. Not so much DWV, but less vitality, lack of vigour, more brood issues of spotty brood with holes in the cappings, and foraging is reduced, no honey or pollen comes in. Bees will feed, take in syrup and pollen sub, but they won't forage so much, and they reduce in populations even with feeding. Something has changed or is changing over, I'd say the last 3-4 years, especially the last 2 year it has been very noticeable. 

For the last two years I treat with Apivar and everything clears up and foraging picks up, honey and pollen gets stored, but a month after the Apivar comes off, it's back again. So what to do, keep treatment on full time? I don't think so, that's not kosher in my book. I've tried treatment free but that does not work here, I got tired of losing 85-100 percent of the hives over winter every year, and even the survivors were so weak and non performing the next year they weren't worth having. And I don't believe that just genetics is the answer, as I've run many different genetics here over the six years I've been here. I'm almost at a loss at this point in time. Right now, I've got a few that came through with less than a half frame of bees, but I put on Apivar starting on December 15, and even that small of population is now working, bringing in pollen and foraging heavy, acting more like bees should be acting when they are healthy. I've got a few that look much better, having 5+ frames of bees and they are doing well also. It looks like most if not all of the hives will make it, time will tell.


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## Oldtimer (Jul 4, 2010)

Hmm, interesting the same thing happening in 2 different countries. Very similar to me, other than things stay good here a bit longer after treatment. I too use Apivar, alternated with other treatments, but after a treatment the bees are normally good for at least 6 months. The worrying thing here is that the other main treatments have become unreliable and many beekeepers are using nothing but Apivar, every time. Meaning in theory at least, it is more likely for resistance to take hold.

Since things in your hives are going down hill so quickly after treatment I'm wondering if something else is at play such as re invasion from other hives? Or, that Apivar is no longer killing a big enough percentage of mites to prevent an early buildup to harmful numbers?
I know you probably thought of all that already, just some thoughts that occurred to me.


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## odfrank (May 13, 2002)

RECENT??? It's been an obvious problem here for ten years or more.


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## RayMarler (Jun 18, 2008)

Oldtimer said:


> Hmm, interesting the same thing happening in 2 different countries. Very similar to me, other than things stay good here a bit longer after treatment. I too use Apivar, alternated with other treatments, but after a treatment the bees are normally good for at least 6 months. The worrying thing here is that the other main treatments have become unreliable and many beekeepers are using nothing but Apivar, every time. Meaning in theory at least, it is more likely for resistance to take hold.
> 
> Since things in your hives are going down hill so quickly after treatment I'm wondering if something else is at play such as re invasion from other hives? Or, that Apivar is no longer killing a big enough percentage of mites to prevent an early buildup to harmful numbers?
> I know you probably thought of all that already, just some thoughts that occurred to me.


Yes, it's from the area I'm in I think, that quick re-infestation happens in the fall, along October time frame. That's when beeyards start moving into my area for over wintering for the California Almond pollination. This last year, a yard moved in 1.5 miles up the road here, 150 hives or so, and I immediately saw a difference in my yard. I had to take feeders off because all the hives got mean from fighting off robbers. The neighbours here started making comments about how mean my bees were, but I explained that my hives have always been here with no one having any problems, and that their issue was from the yard that moved in up the road. That yard was to the east of me, and I know of a larger yard to the south of me, and another yard to the west of me. My only direction safe from hives was to the north, but that's all rice fields and not so much forage there.


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## Oldtimer (Jul 4, 2010)

odfrank said:


> RECENT??? It's been an obvious problem here for ten years or more.


Odfrank nobody is saying PMS is recent, we were talking about that some of us are seeing less deformed wings nowadays, relative to brood damage.


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