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De: http://pakagri.blogspot.com.es/2012/06/honeybee-virus-varroa-mite-spreads.html?goback=.gde_68088_member_123917597
A parasitic mite has helped a virus wipe out billions of honeybees throughout the globe, say scientists.

A team studying honeybees in Hawaii found that the Varroa mite helped spread a particularly nasty strain of a disease called deformed wing virus.

The mites act as tiny incubators of one deadly form of the disease, and inject it directly into the bees' blood.

This has led to "one of the most widely-distributed and contagious insect viruses on the planet".
The findings are reported in the journal Science.

The team, led by Dr Stephen Martin from the University of Sheffield, studied the honeybees in Hawaii, where Varroa was accidentally brought from California just five years ago.

Crucially some Hawaiian islands have honeybee colonies that are still Varroa-free.

This provided the team with a unique natural laboratory; they could compare recently-infected colonies with those free from the parasite, and paint a biological picture of exactly how Varroa affected the bees.

The team spent two years monitoring colonies - screening Varroa-infected and uninfected bees to see what viruses lived in their bodies.

Dr Martin explained to BBC Nature that most viruses were not normally harmful to the bees, but the mite "selected" one lethal strain of one specific virus.

"In an infected bee there can be more viral particles than there are people on the planet," Dr Martin explained.

"There's a vast diversity of viral strains within a bee, and most of them are adapted to exist in their own little bit of the insect; they get on quite happily."

But the mite, he explained, "shifts something".

In Varroa-infected bees, over time, the vast majority of these innocuous virus strains disappear and the bees' bodies are filled with one lethal strain of deformed wing virus.

And when it comes to viral infection, it's the sheer quantity that kills; each viral particle invades a cell and takes over its internal machinery, turning the bee's own body against itself.

Although it is not clear exactly why this strain thrives in mite-infected bees, Dr Martin explained that it could be the one virus best able to survive being repeatedly transmitted from the mites to the bees and back, as the mites feed on the bees' blood.

The effect appears to take once the mites have changed this "viral landscape" in the bees' bodies, the change is permanent.

"So the only way to control the virus is to control the levels of the mite," said Dr Martin.

Prof Ian Jones, a virologist from the University of Reading said the findings mirrored "other known mechanisms of virus spread".

He added: "[This] reinforces the need for beekeepers to control Varroa infestation."
The British Beekeepers Association (BBKA) praised the research.

BBKA chairman Dr David Aston said it "increased our understanding of the relationships between Varroa and [this] significant bee virus."

He told BBC Nature: "These findings underline the need for further research into Varroa.

"There remains a clear and urgent need for an effective, approved treatment."





 Stop the Mass Death of Bees! 
Tell EPA and USDA to ban Bayer's insecticides & Monsanto's GMOs!
Monsanto's Mon810 corn, genetically engineered to produce a synthetic version of the insecticide Bt, has been banned in Poland following protests by beekeepers who showed the corn was killing honeybees. Meanwhile, commercial beekeepers in the U.S. have filed anemergency legal petition with the Environmental Protection Agency (EPA) to suspend use of a pesticide that is linked to massive honey bee deaths. The legal petition, which specifies Bayer's neonicotinoid pesticide clothianidin, is backed by over one million citizen petition signatures.

Poland is the first country to formally acknowledge the link between Monsanto's genetically engineered corn and the Colony Collapse Disorder (CCD) that's been devastating bees around the world, but it's likely that Monsanto has known the danger their GMOs posed to bees all along. The biotech giant recently purchased a CCD research firm, Beeologics, that government agencies, including the US Department of Agriculture, have been relying on for help unraveling the mystery behind the disappearance of the bees. 

Now that it's owned by Monsanto, it's very unlikely that Beeologics will investigate the links, but genetically engineered crops have been implicated in CCD for years now. 

In one German study, when bees were released in a genetically engineered canola field, then fed the canola pollen to younger bees, scientists discovered the bacteria in the guts of the young bees took on the traits of the canola's modified genes. That proves that GMO DNA in pollen can be transferred to bees though their digestive system.

Many bee-keepers have turned to high-fructose corn syrup to feed their bees. High-fructose corn syrup is made from Monsanto's genetically engineered corn and that corn is treated with Bayer's neonicotinoid insecticides.

Bee colonies began disappearing in the U.S. one year after the EPA allowed these new insecticides on the market in 2004-2005. Even the EPA itself admits that "pesticide poisoning" is contributing to bee colony collapse. 

One of the observed effects of these insecticides is weakening of the bee's immune system. Forager bees bring pesticide-laden pollen back to the hive, where it's consumed by all of the bees. Six months later, their immune systems fail, and they fall prey to natural bee infections, such as parasites, mites, viruses, fungi and bacteria. Indeed, pathogens such as Varroa mites, Nosema, fungal and bacterial infections, and IAPV are found in large amounts in honey bee hives on the verge of collapse.

Three recent studies implicate neonicotinoid insecticides, or "neonics" for short, which coat 142 million acres of corn, wheat, soy and cotton seeds in the U.S. alone. They are also a common ingredient in a wide variety of home gardening products. As detailed inan article published by Reuters, neonics are absorbed by the plants' vascular system and contaminate the pollen and nectar that bees encounter on their rounds. Neonics are a nerve poison that disorient their insect victims and appear to damage the homing ability of bees, which may help to account for their mysterious failure to make it back to the hive. 

This was the conclusion of research which came out in the prestigious Journal Science. In another study, conducted by entomologists at Purdue University, the scientists found that neonic-containing dust released into the air at planting time had "lethal effects compatible with colony losses phenomena observed by beekeepers." A third study by the Harvard School of Public Health actually re-created colony collapse disorder in several honeybee hives simply by administering small doses of a popular neonic, imidacloprid.

Learn How to Protect Your Neighborhood Bees:
http://www.honeybeehaven.org/

Fonte: http://www.capwiz.com/grassrootsnetroots/issues/alert/?alertid=22033501&goback=%2Egde_68088_member_114809645#%2ET64SjioAvjw%2Elinkedin



Muerte masiva de las abejas:
http://www.capwiz.com/grassrootsnetroots/issues/alert/?alertid=22033501&goback=.gde_68088_member_114809645#.T64SjioAvjw.linkedin

Entradas Relacionadas:

Insectos Polinizadores

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