# TF success and mite type: any correlation?



## FlowerPlanter (Aug 3, 2011)

As far as I know we only have one varroa sub species in the US. Concerns of others jumping species in Asia could be another threat.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135103

As fast as varroa spread through the entire country/continent in the 90s it is very likely they continually get around just as fast, your mites are my mites...(or soon will be with global trade) If there were a more virulent varroa to include pesticide selected one it's likely to spread just as quick.

As we play around with these mites and throw every pesticide, at every possiable dose. We kill 96% of the weak mites and breed the strongest 4%. At the same time propping up and breeding the weakest bees with more and more treatments needed to keep them alive. We see ever increasing winter losses. Is it the mite or the bee?

>What we know? In some places some queens are successful dealing with varroa mites, but when her daughters are taken to other places do not work so well.

It is likely she and her attendants also bring along mites with them. It seems that when TF bees are taken to areas that have lots of treated bees they can't be TF. When treated bees are taken to isolated areas most don't make it, they go through a genetic bottle neck and possibly a host-parasite coevolution. 

This study might suggest it's the bee's genes that are mite tolerant.
and on a side note the pesticides we give our bees also make them weaker. 

http://www.beesource.com/forums/sho...ance-in-Saskatraz﻿-bees&p=1504547#post1504547


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## Michael Bush (Aug 2, 2002)

As far as I can tell FlowerPlanter is right. We only have the one here, but there is some validity to your question. We are all raising mites whether we like it or not. I want to raise mites that can live with bees and not mites that kill bees.


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## Eduardo Gomes (Nov 10, 2014)

More articles where the two types of varroa destructor and their geographic distribution are mentioned: type K and type J.

F Planter I did not mention sub-species, I mentioned "types" the same designation that the cited author uses.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634981/

https://hal.inria.fr/file/index/docid/890789/filename/hal-00890789.pdf

http://www.um.es/prinum/uploaded/files/actividad/MuÃ±oz et al_JAR08.pdf


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## FlowerPlanter (Aug 3, 2011)

According to your study you just linked in US we have both?

"Randomly amplified polymorphic DNA (RAPD) markers (Kraus & Hunt 1995) also displayed a very low genetic variation within populations. Subsequent RAPD surveys distinguished two types of Varroa (de Guzman et al. 1997): one, the R (for Russian) type corresponded to mites from the United States, Russia, Morocco, Germany, Italy, Spain and Portugal populations and the other, the J (for Japan) type, to populations from Japan, Brazil and Puerto Rico and an admixture of both in North America (de Guzman et al. 1999). These two types carry the Korea and Japan haplotypes, respectively, and following Anderson (2000), are hereafter referred to as Korea or K (= Russia) and Japan or J types. The K type is highly virulent on A. mellifera, but the J type is far less aggressive (Delfinado-Baker 1988)."

If this is true then like I said before they are likely spread across the North America. And likely the more virulent would dominate. "Your mite is my mite".

Many have treatment free bees here most in isolated area away from treated bees. And it seems to be the honey genes not the mite. 

The genetic markers they are using to track the DNA, might also show that these mites are going everywhere and continents do not limit their movement. 

With that we need to be very carful (not just as a country) how we selectively breed our mites. 

>Glycerin oxalic strips tested in Portugal and Spain were not as effective as the results reported in South America. One of the explanatory hypotheses is the difference in varroas' virulence in the two continents. 

Do you think this could be cause Portugal and Spain have been using oxalic acid a lot longer then South America? Selective breeding?;

http://www.beesource.com/forums/sho...how-dangerous-is-Apivar&p=1482139#post1482139


R Oliver;



> Randy Oliver: "Will overuse of oxalic acid result in its becoming just another “Silver Bullet” with a limited effective life, due to mites evolving resistance? I strongly suggest using it to knock back mite levels only once a year. Otherwise, we’ll just be breeding for OA-resistant mites"


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## beemandan (Dec 5, 2005)

FlowerPlanter said:


> And likely the more virulent would dominate.


 Why so?


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## FlowerPlanter (Aug 3, 2011)

beemandan said:


> Why so?


Could it be any other way? 

From ED's post#4, first study;

'We suspect that the last explanation is the correct one; it implies that the K type, far more virulent, is displacing the K type in many countries."

Fom the study in post in #2;

"Since apiculture has facilitated the global transmission of Varroa, selection will inevitably favor the most virulent types in A. mellifera as seen for the global spread of the Korean haplotype."


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## beemandan (Dec 5, 2005)

FlowerPlanter said:


> Could it be any other way?


A couple of folks made the statement....doesn't explain it....at least not to me. 
If I were applying my thinking to it....I'd say it would be the opposite. The more virulent the more likely they kill their hosts. Why would that cause them to be more successful? It probably makes sense but I don't see it.


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## JWChesnut (Jul 31, 2013)

Virulence is associated with horizontal transmission of disease. Mites spread horizontally, as opposed to vertically. The enormous literature researching why some diseases remain or increase in virulence all support the supposition that high horizontal transmission rates encourages virulence.

By maintaining weakened and dying colonies (a la "Bond Testing"), the keepers of these are simply encouraging the propagation of virulent strains.


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## Saltybee (Feb 9, 2012)

Doubtful to me that it is as simple as mite type. ( OR bee gut or mite gut, etc.)
Is the tick carrying Lyme more virulent than the non carrying tick? Probably not to the tick.

From the tick's view a sick sedentary host (below a fatal level) is probably a superior host. 

A collapsing hive is a great vector for the mite.

I see no reason that both a virulent strain and a sub lethal strain would not be to the mite's advantage.


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## FlowerPlanter (Aug 3, 2011)

beemandan said:


> A couple of folks made the statement....doesn't explain it....at least not to me.
> If I were applying my thinking to it....I'd say it would be the opposite. The more virulent the more likely they kill their hosts. Why would that cause them to be more successful? It probably makes sense but I don't see it.


That's exactly what varroa destructor does (did) it killed it's host wiped out 99.99% of feral hives (so they say) and every untreated hive in America in the 90s. The only hives that survived; rare feral hives and the treated domesticated hives. If the varroa destructor was any more virulent we may have lost our feral bees (still poses a threat) and may have to treat our domestic hives more often with stronger pesticides (maybe what we see today). If varroa is too virulent that it kills the host before it could spread then it would not be a problem.

If varroa was not a clonal spices it could breed in lower virulent traits into is their gene pool. Especially if these traits did not kill their host; there would be more of the survivor that did not kill the host verse less survivor that kill the host.



JWChesnut said:


> By maintaining weakened and dying colonies (a la "Bond Testing"), the keepers of these are simply encouraging the propagation of virulent strains.


Not necessary; By maintaining colonies that require treatments "the keepers of these are simply encouraging the propagation of virulent strains.". By what means does one maintain healthy strong colonies; pesticide selection? What if the weakened and dying colonies have more resistance than the treated colonies?


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## Eduardo Gomes (Nov 10, 2014)

FlowerPlanter said:


> Do you think this could be cause Portugal and Spain have been using oxalic acid a lot longer then South America? Selective breeding?


FP in a portuguese survey conducted in 2016 on a sample of 8000 hives 7% were treated with oxalic acid. Oxalic acid treatment is recent in Portugal, unlike northern and central Europe. In our country, given the weather conditions, the brood stop or does not happen or happens for short periods. For this reason I believe that most of portuguese beekeepers are not using it.



Saltybee said:


> Doubtful to me that it is as simple as mite type.


Like you I do not believe in unique causes, timeless and universal, for nothing in this world. This aspect (mite type) could be one more to join to several others.


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## squarepeg (Jul 9, 2010)

attacking the varroa problem from the mite side of the equation does make sense eduardo. i'm not sure much research money is being spent on that but perhaps more should be.

jwchestnut is correct in pointing out that higher virulence is selected for considering horizontal transmission along with the opportunity provided when multiple colonies are located in close proximity to each other. the 'host' is actually the whole bee yard which is usually never completely 'killed'.

what few colonies i've had that did succumb to varroa most often died out during the winter months. i assume the mites that caused the collapse also died out. i've wondered if that dynamic in this area has over time selected for less virulent mites.


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## BernhardHeuvel (Mar 13, 2013)

While you develop a treatment free apiary, you should take samples of your mites continuously. So later you can go back in time and see, how your mites changed or not. I have dozens of small plastic bags with mites from the last ten years that I sampled. Thought it might be interesting to look for some day.


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## 1102009 (Jul 31, 2015)

> Probably the most powerful argument in favour of natural swarming is to do with the control of disease in the bee population. Swarming is associated with only vertical transmission of disease, which theory predicts will select for low pathogen virulence, milder pathogens, if you like.18 This means that if the pathogen kills the host that is the end of the line for both host and pathogen. On the other hand,* multiplying colonies by splitting them,* as is common beekeeping practice, *increases horizontal disease transmission which evolves high pathogen virulence.* This is because the main reservoir for disease is usually the brood combs and the brood in them. If the pathogen kills off one part of a split there is still a chance for another part to survive and propagate the pathogen. It is not the end of the line for the pathogen. And even if all parts of a split fail there is still infected comb and equipment present to spread disease, e.g. through robbing. Helped by common beekeeping practices, pathogens can freely develop their virulence. For example, their reproductive fitness can increase, as there is less incentive to curb it sufficiently to allow the infected colony to swarm
> and thus secure the pathogen's survival by vertical transmission. The result is selection for increased lethality of pathogens.


Out of David Heafs website.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.9.7475&rep=rep1&type=pdf


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## BernhardHeuvel (Mar 13, 2013)

There is no practical way to keep bees as isolated as would be needed to hinder horizontal transmission. Bees every 800 meters? Yeah, right...


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## BernhardHeuvel (Mar 13, 2013)

There is no practical way to keep bees as isolated as would be needed to hinder horizontal transmission. Bees every 800 meters? Yeah, right...


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## FlowerPlanter (Aug 3, 2011)

Eduardo Gomes said:


> FP in a portuguese survey conducted in 2016 on a sample of 8000 hives 7% were treated with oxalic acid.


7% for how many decades? Europe has been using oxalic acid for a long time (believe longer than anyone else). America just recently picked it up (have no idea about South America seeing how they have a high percent Africanized that are mite tolerant I suspect there's not much oxalic acid use in resent or past, they also seem to be the world leader in organic honey). Do you all import and export bees/queens freely from Europe? 



squarepeg said:


> i've wondered if that dynamic in this area has over time selected for less virulent mites.


An inbred clonal spices that is genetically identical to its parents. If there was a genetic mutation with a lower virulent would it be quickly displaced? As the above studies suggest the displacement of the less "virulent J type". 



SiWolKe said:


> On the other hand, multiplying colonies by splitting them, as is common beekeeping practice, increases horizontal disease transmission which evolves high pathogen virulence.


This has more to do with brood diseases, mostly bacterial and contaminated comb play a big part, but can also be carried with new swarms. The viruses that mites carry do not seem to contaminate the comb and have more to do with high mite counts and the bee's resistance and tolerance to both mites and the viruses. 



BernhardHeuvel said:


> There is no practical way to keep bees as isolated as would be needed to hinder horizontal transmission. Bees every 800 meters? Yeah, right...


I believe you're correct, they would need to be separated by continents and this still proves a challenge. "your mite is my mite". And as these studies suggests the more virulent; type, crossbreed or selected mite will dominated.


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## squarepeg (Jul 9, 2010)

flowerplanter, is it known how long the viruses persist in the hive once the bees and mites die out?


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## BadBeeKeeper (Jan 24, 2015)

SiWolKe said:


> > Probably the most powerful argument in favour of natural swarming is to do with the control of disease in the bee population. Swarming is associated with only vertical transmission of disease, which theory predicts will select for low pathogen virulence, milder pathogens, if you like.18 This means that if the pathogen kills the host that is the end of the line for both host and pathogen. On the other hand, multiplying colonies by splitting them, as is common beekeeping practice, increases horizontal disease transmission which evolves high pathogen virulence. This is because the main reservoir for disease is usually the brood combs and the brood in them. If the pathogen kills off one part of a split there is still a chance for another part to survive and propagate the pathogen. It is not the end of the line for the pathogen. And even if all parts of a split fail there is still infected comb and equipment present to spread disease, e.g. through robbing. Helped by common beekeeping practices, pathogens can freely develop their virulence. For example, their reproductive fitness can increase, as there is less incentive to curb it sufficiently to allow the infected colony to swarm
> > and thus secure the pathogen's survival by vertical transmission. The result is selection for increased lethality of pathogens.
> 
> 
> ...


The terms 'pathogen' and 'virulence' are typically applied to microbial disease-producing organisms. I do not believe it is either correct or appropriate to apply them to mites, and doing so introduces confusion and misunderstanding of the nature and characteristics of the mites and how to deal with them. Mites are an opportunistic parasite that -host- certain pathogens which are capable of infecting bees, but they are not a pathogen themselves and that quote is not applicable to them.

I do note that some [other] articles use the term 'pathogen' in regard to varroa so I am not faulting anyone specifically for the usage, I am merely suggesting that such usage is incorrect and tends to distract/misdirect from a true understanding of the nature of varroa mites. The nature of your enemy must be understood correctly if you are to develop effective strategies to fight him.

As an aside, I just ran across this in regard to the Chinese black honey bee, and it seems interesting:

https://www.ars.usda.gov/research/publications/publication/?seqNo115=314017


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## Saltybee (Feb 9, 2012)

In a high density bee population a virulent mite would do relatively well, not overrun it's host prematurely.
In a low density bee population a less virulent mite would succeed better.
To every niche there is a parasite to fill it.


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## FlowerPlanter (Aug 3, 2011)

squarepeg said:


> flowerplanter, is it known how long the viruses persist in the hive once the bees and mites die out?


The word around here is it's safe to use mite dead out equipment on new bees, DWV possibly the main cause of dead outs seems to disappear with the bees. Although misdiagnosis of dead outs is common can cause reinfection of bacterial diseases, often seen with EFB sometimes seen with nosema, caulk brood and AFB.

http://articles.extension.org/pages/71172/honey-bee-viruses-the-deadly-varroa-mite-associates

"One of the serious problems caused by Varroa is the transmission of viruses to honey bees which cause deadly diseases. Viruses found in honey bees have been known to scientists for 50 years and were generally considered harmless until the 1980’s when Varroa became a widespread problem."

"Therefore controlling Varroa populations in a hive will often control the associated viruses "

"Control of DWV is usually achieved by treatment against Varroa, After treatment a gradual decrease in virus titers occurs as infected bees are replaced by healthy ones (Martin et al 2010)."


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## squarepeg (Jul 9, 2010)

badbeekeeper, i think 'virulence' when applied to mites is describing how successful or not the mites are at reproducing and achieving a high infestation rate. the bees have traits which limit mite reproduction and the mites have traits to thwart the bees attempts at doing so. 

i think it's within the realm of reason to consider that less virulent mites may be selected for if horizontal transmission is somehow limited, such as may be the case when a colony collapses during the winter months and the more virulent colony collapsing mites also die off prior to being spread to nearby colonies via robbing.

it's for this reason that i've decided to euthanize a colony should i find it on it's deathbed prior to winter, thereby winnowing out not only the bee genetics unable to resist collapse by varroa, but also removing the potentially more harmful strain of mites as well.

an alternative to euthanizing could be to remove the collapsing colony to a safe location, dequeen it, kill the mites with treatment, and requeen with more proven genetics. a possible drawback to this approach would be if especially virulent strains of viruses remained after varroa treatment and those viruses were able to build back up to high titers again.

i do not know to what extent the more virulent strains of viruses also die off along with the mites in winter dead out and euthanizing scenarios, and i was unable to locate any studies that have looked at how long bee viruses remain viable once their host dies. i've posed the question to the mailing list at bee-l to see if any of those in the science communty might know.


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## 1102009 (Jul 31, 2015)

squarepeg said:


> an alternative to euthanizing could be to remove the collapsing colony to a safe location, dequeen it, kill the mites with treatment, and requeen with more proven genetics. a possible drawback to this approach would be if especially virulent strains of viruses remained after varroa treatment and those viruses were able to build back up to high titers again.


Hey SP, my path! Thanks for mentioning this. The only possibility not to loose bee amount but improve stock if you have no ferals.

If we fear more virulent viruses we should quit beekeeping.
The virulent viruses may appear suddenly with some swarms or a migrating beekeeper or some honey the bees steal out of garbage, who nows.
And who knows if there are some mite mutations in your hives?

Our bees must be able to bear this with some losses for sure but with survivors too. 
We must manage them in such a way they are able to overcome such a situation.


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## squarepeg (Jul 9, 2010)

if it turns out that especially virulent viruses or their virions persist in the hive following the death of the bees and the mites, it may be helpful for example to use diluted bleach or something similar to 'disinfect' dead out comb and hive bodies prior to reusing them.

if the current study underway by stephen martin and randy oliver ends up showing that the less virulent form of dwv predominates in successful untreated colonies...

it might mean in addition to dequeening, treating, and requeening as considered above, it may prove useful to 'inoculate' such a colony with a frame of brood from a successful untreated colony as well...

(the goal being to potentially promote the less virulent strain of dwv which has been found to displace the more virulent strain in preliminary studies).


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## JWChesnut (Jul 31, 2013)

Current issue of the Western Apicultural Society journal has a synopsis of the Hawaii conference where Dr. Martin and his co-investigators presented. 

One aspect of this discussion concerned the island off Brazil where published papers hypothesized that "fast evolution" solved the Varroa problem. Dr. Martin's investigator presents an entirely different interpretation -- the island is a "ticking time bomb" and the low bee density and (possible) mite origin has --temporarily-- delayed the more normal worldwide expansion of the virulent strain.









Cite : http://digitalwasjournal.advancedpublishing.com/?issueID=25&pageID=16


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## Saltybee (Feb 9, 2012)

squarepeg said:


> it might mean in addition to dequeening, treating, and requeening as considered above, it may prove useful to 'inoculate' such a colony with a frame of brood from a successful untreated colony as well...


My suspicion is an isolated yard may also have a great advantage over mixing in with regular hives. I wonder to what extent the inoculation flows both ways. Is a full nuc the most practical, or the only practical?


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## squarepeg (Jul 9, 2010)

my apologies saltybee, i'm not sure i understand the question, can you rephrase it please?


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## Eduardo Gomes (Nov 10, 2014)

FlowerPlanter said:


> 7% for how many decades? Europe has been using oxalic acid for a long time (believe longer than anyone else). America just recently picked it up (have no idea about South America seeing how they have a high percent Africanized that are mite tolerant I suspect there's not much oxalic acid use in resent or past, they also seem to be the world leader in organic honey). Do you all import and export bees/queens freely from Europe?


From what I know the use of oxalic acid is recent in Portugal. One of the reasons has already been mentioned by me (the formic acid in the survey I have mentioned has a greater use than the oxalic acid, perhaps because it is more suitable to deal with brood present, but I do not know the specific reasons). The other is related to the fact that only about 2 years ago the oxalic acid treatment was approved to treat bees by the portuguese veterinary authorities.

We bought few queens to other countries because we have an indigenous bee in the Iberian Peninsula. The F2, F3 hybrids from another strain are not appreciated. The vast majority of portuguese beekeepers work with the local bee.


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## Saltybee (Feb 9, 2012)

squarepeg said:


> my apologies saltybee, i'm not sure i understand the question, can you rephrase it please?


Continuation of your thought on the benefits of adding a frame instead of just a queen. Speculating that only a frame in a treated yard with treated bees making up the rest of the hive greatly reduces any chance of successfully transferring the TF traits.

Isolation as a establishment mode.


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## squarepeg (Jul 9, 2010)

understood saltybee, thanks for the clarification.

i agree that just adding one frame wouldn't accomplish much in that scenario.

the isolation yard i had in mind was in the context of what sibylle is going to try this year, whereby she is going to relocate troubled hives from her treatment free yard over to a 'hospital' yard. 

if i am understanding correctly, these troubled and relocated hives will be treated and requeened. these are the ones i was talking about 'inoculating' with a frame from a successful colony, not for introducing traits, but rather to introduce potentially beneficial microbiota like perhaps the b variant of dwv.

since i haven't done any of that nor am i aware of anyone who is, all of this is pure speculation and an extreme case of arm chair quarterbacking.

jwchestnut, i noticed that 'inoculation' was also mentioned in the blurb you posted.


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## squarepeg (Jul 9, 2010)

here is a link to the study describing the less virulent dwv b variant:

http://www.nature.com/ismej/journal/v10/n5/full/ismej2015186a.html

from the paper:

"We propose that this novel stable host-pathogen relationship prevents the accumulation of lethal variants, suggesting that this interaction could be exploited for the development of an effective treatment that minimises colony losses in the future...

...the direct introduction of DWV type B could provide a form of biocontrol against further collapse of European honey bee colonies in the face of Varroa infestation."

randy oliver collected bee samples from treated and untreated colonies from across the u.s. and sent them to dr. martin a couple of months ago for analysis, which included samples from 5 of my colonies.


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## Nordak (Jun 17, 2016)

" 'inoculating' with a frame from a successful colony, not for introducing traits, but rather to introduce potentially beneficial microbiota like perhaps the b variant of dwv."

I never thought of this as a factor in the sense of inoculation, but when I requeened before I added a couple of frames of brood from a healthy colony. In fact, I've swapped frames around a lot and have seen less and less signs of DWV, none this past year that I noticed. Although speculative, there very well may be something to this. If faced with that choice again, I'll certainly make the same call. Thanks for pointing this out. Can't hurt, that's for sure.


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## 1102009 (Jul 31, 2015)

squarepeg said:


> i agree that just adding one frame wouldn't accomplish much in that scenario.
> the isolation yard i had in mind was in the context of what sibylle is going to try this year, whereby she is going to relocate troubled hives from her treatment free yard over to a 'hospital' yard.
> if i am understanding correctly, these troubled and relocated hives will be treated and requeened. these are the ones i was talking about 'inoculating' with a frame from a successful colony, not for introducing traits, but rather to introduce potentially beneficial microbiota like perhaps the b variant of dwv.


Thanks SP the informations in this thread makes me overthink the "hospital" idea to improve it.
Isolating those hives was my idea to prevent the others from spread of disease but now my idea is to actively try to improve the failing hives with beneficial material.
Very good!



> Ironically, it may be the presence of the mite population that is protecting the colony as Varroa may be providing the opportunity for constant re-introduction of type B into the population via horizontal transmission.


Last year, in my exchange of e-mails with Erik Österlund he advised me to introduce foreign stock only in small amounts, for example if I had ten hives, introduce one nuc.
Works like a vaccination, maybe. Wisdom in this. With swarms introduced could be the same or putting those in isolation first to check or send a sample.

Second advise was to use only ten to twelve hives in one location so if they crash you have stock to go on. Place the hives with distance and the entrances in different directions, reminds me of T.Seeley now.



> Therefore, the Swindon UK population in question could have evolved to favour DWV type B persistence as a result of husbandry practices that have selected for a new stable non-pathogenic equilibrium.





> Accordingly, the direct introduction of DWV type B could provide a form of biocontrol against further collapse of European honey bee colonies in the face of Varroa infestation.


Hope this will be promoted.


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## Saltybee (Feb 9, 2012)

Is the goal to innoculate existing hives or start TF hives.
To me inoculating existing hives is a little like bringing a healthy person into a house full of flu victims to cure them.The numbers are not on your side.

I read somewhere on BS that in a combined hive it is the gut of the house bees, not the nurse bees, that prevails in the end. That raises a mite virus question. When does a mite become a carrier? From an adult bee or from a larva? Via mite egg ?

The point being a brood frame may not be a particularly good inoculant. Pulling brood and then moving the donor hive to concentrate house bees may give a better donor medium (house bees) than a brood frame. A house bee package if you will.


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## squarepeg (Jul 9, 2010)

not much is understood at this point about what role if any that microbes play in allowing survivor bees to do well off treatments. 

the dwv a/b study may shed some light, and if it pans out, my guess is that there will be a method developed other than moving frames of brood for inoculating colonies.

if microbes do matter, that would tend to suggest better success with the making of splits off of tf colonies vs. trying to only requeen a nonresistant colony with a tf queen.


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## BadBeeKeeper (Jan 24, 2015)

Saltybee said:


> To me inoculating existing hives is a little like bringing a healthy person into a house full of flu victims to cure them.


Think of it more as what, years ago, some mothers did when a kid in the area came down with Chicken Pox- they would get together and intentionally expose their healthy kids to the infected one so that they would catch it too. They did it because it was said that catching the Pox as an adult was far worse than having it as a kid, and they believed they were doing their kids a favor by exposing them to it while they were young.

Unfortunately, due to a lack of knowledge of the nature of the disease, they unwittingly guaranteed that a large percentage of those children would be subject to the agonizing and debilitating effects of Shingles as adults.

Man meddling with Nature often results in unintended consequences, especially when one does not fully understand the nature of the Nature one is meddling with...and the consequences that might arise.

Even so-called 'experts' are not always right, and they fail to foresee all of the potential consequences of their actions, resulting in disaster somewhere down the line.


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## 1102009 (Jul 31, 2015)

Had to look up >inoculation<...ok.

I don´t think you can compare to inoculate a failing hive with a brood frame from disease tolerant bees to a measles party.
You don´t take the brood frame back.

Just be careful not to introduce other brood disease.


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## squarepeg (Jul 9, 2010)

in the nature paper linked above, the concept of superinfection exclusion is used imply that the less virulent strain of dwv somehow displaces the more virulent strain, and is presented as a possible explanation for why some untreated survivor colonies are able to cope with higher mite levels than are typically tolerated. if true than simply introducing some of the less virulent strain would presumably result in a shift to the less virulent strain over time.


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## squarepeg (Jul 9, 2010)

BadBeeKeeper said:


> Man meddling with Nature often results in unintended consequences, especially when one does not fully understand the nature of the Nature one is meddling with...and the consequences that might arise.


i agree with this statement, but the same holds true when it comes to introducing miticides into the hive. it is unknown is to what degree potentially beneficial organisms are also removed from the hive ecosystem in the process. 

it is within the realm of possibility that an unintended consequence of killing mites is altering the microbial population in such a way as to leave the bees vulnerable to other problems.

i'm wondering if the higher winter losses being reported across the northern u.s. in recent years may turn out to have something to do with this.


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## BadBeeKeeper (Jan 24, 2015)

squarepeg said:


> badbeekeeper, i think 'virulence' when applied to mites is describing how successful or not the mites are at reproducing and achieving a high infestation rate. the bees have traits which limit mite reproduction and the mites have traits to thwart the bees attempts at doing so.
> 
> i think it's within the realm of reason to consider that less virulent mites may be selected for if horizontal transmission is somehow limited, such as may be the case when a colony collapses during the winter months and the more virulent colony collapsing mites also die off prior to being spread to nearby colonies via robbing.


And...this sort of thinking is exactly why I think that the term should remain applied only to virii, and not to critters such as mites. Mite reproduction is fairly fixed, in that the 'foundress' lays a limited number of eggs per cell, she cannot lay more because too many would result in the premature death of the bee larva on which the young mites feed, which in turn would result in the mites not maturing enough to become sexually viable and able to themselves reproduce. (I lost my link to the study that discussed this aspect of mite reproduction, but I believe that I am recalling it accurately.)

Mite reproductive strategy is limited to: ride host until cell with egg is available, find cell with egg, lay eggs. It does not matter, to the mite, how it gets to the empty cell, whether it is in the same colony or a different colony. It does not matter to the mite, whether the colony lives or dies, swarms or absconds, or is carried to another hive by a robber. These things are incidental, and so long as one mite survives to reproduce, the geometric progression of its reproduction is sufficient to ensure the survival of the species. It simply does not need to become 'more virulent'.

Evolutionary change/progression requires a pressure that that results in a particular trait becoming either more or less favorable to the survival of the species, in which the trait confers an advantage or disadvantage to survival such that those with the advantage tend to survive and those without it tend to die off. Absent any such interference/pressure imposed by the beekeeper or the bees, the current inherent reproductive strategy of the mites is sufficient to ensure their survival, thus there is no change in selection or 'virulence'. An example of pressure that induces a change is the use of chemical controls such as Coumaphos and tau-Fluvalinate, in which susceptible mites die and resistant mites survive.

On the other side of this is the example of 'swarmy' bees appearing to be more able to tolerate the presence of mites. The mites introduce a pressure to the bees and their survival is enhanced by swarming, thus bees that tend to swarm more often gain a survival advantage. Unfortunately (for beekeepers), this trait results in lower production and increased management issues contrary to the needs of those keeping bees as livestock to produce a saleable commodity/service. In addition, the 'swarmy' trait that enhances the survival of the bees not only does not confer any disadvantage to the mites, it actually _enhances_ their survival and propagation...and it does not require any change in reproductive strategy or 'virulence' on the part of the mites, their extant traits already are sufficient and no change is necessary.




> i do not know to what extent the more virulent strains of viruses also die off along with the mites in winter dead out and euthanizing scenarios, and i was unable to locate any studies that have looked at how long bee viruses remain viable once their host dies. i've posed the question to the mailing list at bee-l to see if any of those in the science communty might know.


The average virus has a relatively short lifespan absent a host, suitable propagation medium in a lab, or suitable preservation (such as the particular strain of flu virus recovered from bodies buried in Alaskan permafrost which allowed the recreation of the Spanish flu virus that caused the 1918 epidemic). Bacteria are another issue, as is the fungal diseases such as Nosema in which the spore stage can remain viable for a much longer time than a virus.


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## Saltybee (Feb 9, 2012)

squarepeg said:


> if true than simply introducing some of the less virulent strain would presumably result in a shift to the less virulent strain over time.


One possible method would be to set up an isolated TF nuc as a drone factory by using drone comb frames as the inoculant. Dependent on the actual life stage of bee/mite where/when the virus is transferred.

Several years ago I started a threaded pondering raising a better mite. Got a little roasted then. Oh well.


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## 1102009 (Jul 31, 2015)

I believe BBK is right about the virulence.
It explains why hives with a low mite count are susceptible to virus disease, too.

The swarming propagates the mites survival just like the drifting, it´s only that a time without brood is balancing the coexistence to a level host and parasite are both able to survive.


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## BadBeeKeeper (Jan 24, 2015)

squarepeg said:


> i agree with this statement, but the same holds true when it comes to introducing miticides into the hive. it is unknown is to what degree potentially beneficial organisms are also removed from the hive ecosystem in the process.


Yes, that is certainly not excluded from the equation.




> it is within the realm of possibility that an unintended consequence of killing mites is altering the microbial population in such a way as to leave the bees vulnerable to other problems.
> 
> i'm wondering if the higher winter losses being reported across the northern u.s. in recent years may turn out to have something to do with this.


Personally, I think that may have more to do with the management decisions/actions (or lack thereof) by the beekeepers reporting. My results do not reflect an increase in losses which can be attributed to that. I do experience some queen loss because I do not re-queen all of my hives every year, I typically allow them to age-out naturally. I raise enough queens to have some on-hand if needed for expected losses, and new queens are purchased only when I want to introduce new genetics in my sloppy, lazy and only slightly guided breeding program.


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## Saltybee (Feb 9, 2012)

BadBeeKeeper said:


> Mite reproductive strategy is limited to: ride host until cell with egg is available, find cell with egg, lay eggs. It does not matter, to the mite, how it gets to the empty cell, whether it is in the same colony or a different colony. It does not matter to the mite, whether the colony lives or dies, swarms or absconds, or is carried to another hive by a robber. These things are incidental, and so long as one mite survives to reproduce, the geometric progression of its reproduction is sufficient to ensure the survival of the species. It simply does not need to become 'more virulent'.
> 
> I doubt it is that simple. Is the drone preference simply the longer cycle , size etc. Or does the greater drift of a drone work for the mite. Is leaving the worker class healthier longer better for mite survival ? I think so.
> Never underestimate the enemy.
> ...


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## squarepeg (Jul 9, 2010)

BadBeeKeeper said:


> Personally, I think that may have more to do with the management decisions/actions (or lack thereof) by the beekeepers reporting. My results do not reflect an increase in losses which can be attributed to that.


i appreciate your thoughtful and civil replies bbk.

are you noticing any trending over the years, (as some are reporting), in terms of having to apply more treatments more often and/or is it becoming necessary to maintain progressively lower infestation rates to avoid problems with your colonies?

if not i believe i would come to the same conclusion as you have. if so, then i would lean toward the possibility that the treatments may be promoting more successful mite reproduction and more virulent virii.


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## BadBeeKeeper (Jan 24, 2015)

squarepeg said:


> i appreciate your thoughtful and civil replies bbk.


LOL, no problem. My intention is actually somewhat selfish, in that discussions in this particular thread lead me to avenues of research that further my understanding of varroa mites (and other pests) and how to deal with them. Know your enemy and all that...



> are you noticing any trending over the years, (as some are reporting), in terms of having to apply more treatments more often and/or is it becoming necessary to maintain progressively lower infestation rates to avoid problems with your colonies?


Actually, quite the opposite- in 2015 I treated only once, and had 100% survival over the Winter. For 2016, my boards did not show high mite levels at the end of the Summer, and I treated only once (in Sept?), and only 2/3 (I think) of my hives. How -that- turns out is yet to be seen, I still have some weeks of Winter left yet. The untreated hives were all open-mated daughter queens of VSH hybrids, that I raised myself, a couple of which were combined (in late Fall) with swarms from my own yard which were presumably VSH or the daughters thereof (I'm not sure exactly which colonies swarmed, it is possible that they -may- have been Carniolans...I sort of lost track of how many of which I had...trying to get better in my record-keeping but still somewhat slacking...).

The time between now and April/May will tell a story...whether it has a good ending or a bad ending is too early to say.


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## lharder (Mar 21, 2015)

I know of some beekeepers that have used chemical controls, switched to organics, started doing mite counts and are shocked at the number of mites, and that the colony still looked ok. 

Could it be that with mites developing resistance to some chemical controls, that some beekeepers have become TF inadvertently? I should mention that I got a queen from that same keeper and she has out performed the Saskatraz stock in longevity and production.


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## FlowerPlanter (Aug 3, 2011)

squarepeg said:


> randy oliver collected bee samples from treated and untreated colonies from across the u.s. and sent them to dr. martin a couple of months ago for analysis, which included samples from 5 of my colonies.


What type of DWV did you have? All your hives the same type? Do you ever see deformed wings? Do they know what types they found in Arnot and other TF? 

How does an isolated TF apiary in UK have that same type DWV in isolated successful TF apiaries in the US, France and Brazil? Separate evolution? Or did it spread but favorable conditions enabled Type B to dominate over Type A?

Do we know enough about Type B that it's the reason the bees are still alive and it's not the genes of the bees?

Maybe as you suggested microbes are part of the equation. Maybe microbes and the bees.

I wonder if anyone has taken successful TF hives treat them with everything under the sun. Then quit and see what happens.


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## squarepeg (Jul 9, 2010)

the results from the samples haven't come in yet flowerplanter. 

it's pretty rare for me to see dwv here, usually only just a few bees from perhaps 1 or 2 out of the 20 or so hives, and usually after the summer dearth and at the beginning of the fall brood up.

it's a fairly new avenue of research and it's too early to say whether or not there will be fruitful insights gained. i'm not aware of any researchers at this point who are looking in a methodical way to see what impact if any treatments have on other life forms in the hive.

it would be a fair question in my opinion to address whether or not treatments favor the predominance of dwv-a vs. dwv-b.


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## JWChesnut (Jul 31, 2013)

A 2017 paper shows that DWV infection (without any visible macro-symptoms) is deadly to colonies.

Frequently hobby beeks remark on the mysterious decline of colonies, and this paper makes clear that uncontrolled Varroa with its attendant viral infection is a prime culprit in this syndrome.

Free download: https://lirias.kuleuven.be/bitstrea...naets_etal_procb_2017_with+suppl+material.pdf

In particular, our experiments show that adult workers injected with low doses of DWV
experienced increased mortality rates, that DWV caused workers to start
foraging at a premature age, and that the virus reduced the workers’ total
activity span as foragers. Altogether, these results demonstrate that covert
DWV infections have strongly deleterious effects on honeybee foraging
and survival.​
Cite this article:
Benaets K et al . 2017 Covert deformed wing virus infections have long-term deleterious effects on honeybee foraging and survival.
Proc. R. Soc. B 284 : 20162149.
http://dx.doi.org/10.1098/rspb.2016.2149


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## Riverderwent (May 23, 2013)

JWChesnut said:


> A 2017 paper shows that DWV infection (without any visible macro-symptoms) is deadly to colonies.


This is an important study. Thank you for sharing.


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## Saltybee (Feb 9, 2012)

JWChesnut, 
What is known of the normal DWV transmission within the hive? Does the mite pickup the virus as a larva because the bee larva has already been infected through feeding? Adult mite spreads only after feeding on adult carrier bee to bee?
Mite to mite egg?
Adult bee to adult bee through contact?
Understanding circulation of virus in the hive will govern injection of variant and best method of cleaning up existing hives.
If bee larva are already infected through feeding that adds a complexity to saving a population. Killing mites leaves a carry forward mechanism through bee to bee feeding. It conversely also opens a inoculation window.


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## squarepeg (Jul 9, 2010)

squarepeg said:


> i was unable to locate any studies that have looked at how long bee viruses remain viable once their host dies. i've posed the question to the mailing list at bee-l to see if any of those in the science communty might know.


peter borst dug in and was able to come up with this:

http://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A2=bee-l;5bfb6e3e.1702


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## BadBeeKeeper (Jan 24, 2015)

squarepeg said:


> peter borst dug in and was able to come up with this:
> 
> http://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A2=bee-l;5bfb6e3e.1702


And mined for summary of relevant content...



> It is widely stated by experts working in the field, including the author of
> the submission, that DWV in particular and bee *viruses in general are unable to
> survive outside the host cell for a long period* (Chen (pers. comm.)17, de Miranda
> (pers. comm.)18, Todd and de Miranda (2004)19).


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## Juhani Lunden (Oct 3, 2013)

FlowerPlanter said:


> How does an isolated TF apiary in UK have that same type DWV in isolated successful TF apiaries in the US, France and Brazil?



Is there a study of this, do you have a link?


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## FlowerPlanter (Aug 3, 2011)

Juhani Lunden said:


> Is there a study of this, do you have a link?


DWV B found in UK is discussed in above studies. They also mention Arnot forest in the US, a forest in France and an island in Brazil where bee have developed resistance but don't actually say it's DWV B or not. Along with SP post about R. Oliver studying TF bees across the US for DWV B and a possiable link to survivor stock. If it is DWV B then How does it get around in isolated TF apiaries and not everywhere else, or is it already everywhere? It opens up many more questions.



squarepeg said:


> the results from the samples haven't come in yet flowerplanter.
> 
> it's pretty rare for me to see dwv here, usually only just a few bees from perhaps 1 or 2 out of the 20 or so hives, and usually after the summer dearth and at the beginning of the fall brood up.


The reason I asked, was pondering that if DVW B does not kill the hive do you still see deformed wings and is that an indication of the type of DWV. Since you see very few, I also see very few, it is possiable that we have the same type of DWV, whichever type it may be. Guess we'll just have to wait and see.


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## Nordak (Jun 17, 2016)

Regarding the DWV scenario, if I understand it correctly, can't it be spread from queen to offspring? The reason I ask is I have had an instance where a queen from an outside source had more visual signs of DWV than my other established hives. Last year this queen swarmed, and I didn't see any more noticeable signs afterward of DWV. If this is the case, we should definitely be careful bringing in foreign genetics even if it's just a queen. I'd definitely like to study up more on these modes of viral transmission.


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## Saltybee (Feb 9, 2012)

Obviously bee larva is already infected or wings would not be deformed. That would appear to bee to bee feeding transfer rather than mite bite transfer. Bee to bee would require a longer time period to become dominant but would be somewhat self sustaining even after mite removal.

Testing bee larva with mites compared to larva without mites would be interesting.
Along that line of thought; would TF nurse bees be a better inoculant than a TF queen? The answer depends on the moment of transfer. That moment may well be as Nordak wonders. 

Of course there may well be multiple moments of transfer. Time till collapse may well vary simply from point of transfer variation, with a drifting field bee taking a fairly long time working back down to a heavy bee to bee feed transfer.


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## Juhani Lunden (Oct 3, 2013)

Nordak said:


> Regarding the DWV scenario, if I understand it correctly, can't it be spread from queen to offspring? The reason I ask is I have had an instance where a queen from an outside source had more visual signs of DWV than my other established hives. Last year this queen swarmed, and I didn't see any more noticeable signs afterward of DWV. If this is the case, we should definitely be careful bringing in foreign genetics even if it's just a queen. I'd definitely like to study up more on these modes of viral transmission.


Did you consider that the queen would have been more susceptible to virus, genetically?


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## Nordak (Jun 17, 2016)

Juhani, I don't want to name names, but this was a queen from one of the most reputable and trusted TF apiaries in the US. They were excellent bees, and despite the fact they had visually more DWV than existing hives, thrived for two seasons before taking off. My guess is if they found a good home, they're probably still out there somewhere. That being said, it's certainly still a possibility taking into account she was open mated.


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## Nordak (Jun 17, 2016)

Interesting article involving vertical transmission of different viruses, DWV being one of the most prevalent in occurence. 

https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-015-0386-9

Hopefully someone more scientifically versed can explain the implications behind these findings.


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## Saltybee (Feb 9, 2012)

Nordak,
Helps me fill in my blanks. Thanks


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## BadBeeKeeper (Jan 24, 2015)

BadBeeKeeper said:


> The time between now and April/May will tell a story...whether it has a good ending or a bad ending is too early to say.


Went out to plow yesterday and it was warm enough to make some quick checks...one dead- evidence of dysentery inside the hive (no Fum-B fed in Fall), plenty of stores, bees spread across six frames...and it was the only hive without an entrance reducer, my bad. Guessing a sub-zero wind got them when they were already suffering. Won't know more for a while, we're back to frigid and it's blowing up a blizzard.


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## Eduardo Gomes (Nov 10, 2014)

Saltybee said:


> Never underestimate the enemy.
> 
> Agree the mite does not need to be virulent, the mite is not even the lethal weapon.


With all due respect, the mite is also the lethal weapon. It is interesting to note that the virus (VDV-1 and DWD) exists in areas where the mite does not exist. The virus is the bullet, but the mite is the gun that shoots the bullet. 

According to some studies is the bite of the mite in the bees' larvae, which introducing the virus into their hemolymph, that makes them so dangerous and virulent. The existence of virus _per se_/without mites is relatively innocuous for bees… unless best opinion.


"Varroa destructor virus-1 (VDV-1) is genetically closely related to DWV but is reported to be more specific to Varroa destructor than to bees (Ongus, 2006). However, both viruses replicate in varroa mites as well as in honey bees (Ongus et al., 2004; Yue and Genersch, 2005; Zioni et al., 2011); both have been detected at high titres in different honey bee tissues (Zioni et al., 2011; Gauthier et al., 2011); *both have been found in regions where V. destructor is absent* (Martin et al., 2012) and natural recombinants between them have been found (Moore et al., 2011). VDV-1 and DWV therefore appear to co-exist in bees and mites as part of the same species-complex (de Miranda and Genersch, 2010; Moore et al., 2011; Gauthier et al., 2011; Martin et al., 2012)."

sources: http://www.coloss.org/beebook/II/virus/1/1/4 and http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1004230


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## Saltybee (Feb 9, 2012)

Eduardo,

Not a lot of respect due when it comes to mites and viruses. Do not mind showing ignorance when it gets me answers.
Interesting links you posted. Thanks.


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