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Posted14 September 2007

Virus Is Newest Suspected Bee-Killer

Below I have included the most recent science report, a press report and a description of the acute bee paralysis virus the prime suspect in CCD. The authors of the Science paper were careful to acknowledge that factors including pesticide exposure that effects the bee immune system may be contributors to the virus infection. The suspect virus, Israeli Acute Paralysis virus is a conventional small RNA virus which has a unique tendency to integrate DNA copies of some of its sequences into the bee genome even though it is not a retrovirus. The virus must be helped in that practice by a retrotransposon or retrovirus in the bee but not yet identified.
(Professor Joe Cummins)

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Published Online September 6, 2007

Science DOI: 10.1126/science.1146498 science magazine

A Metagenomic Survey of Microbes in Honey Bee Colony Collapse Disorder Diana L. Cox-Foster 1, Sean Conlan 2, Edward C. Holmes 3, Gustavo Palacios 2, Jay D. Evans 4, Nancy A. Moran 5, Phenix-Lan Quan 2, Thomas Briese 2, Mady Hornig 2, David M. Geiser 6, Vince Martinson 7, Dennis vanEngelsdorp 8, Abby L. Kalkstein 1, Andrew Drysdale 2, Jeffrey Hui 2, Junhui Zhai 2, Liwang Cui 1, Stephen K. Hutchison 9, Jan Fredrik Simons 9, Michael Egholm 9, Jeffery S. Pettis 4, W. Ian Lipkin 2*

1. Department of Entomology, The Pennsylvania State University, 501 ASI
building, University Park, PA 16802, USA.
2. Center for Infection and Immunity, Mailman School of Public Health,
Columbia University, New York, NY 10032, USA.
3. Center for Infectious Disease Dynamics, Department of Biology, The
Pennsylvania State University, Mueller Laboratory, University Park, PA
16802, USA.; Fogarty International Center, National Institutes of
Health, Bethesda, MD 20892, USA.
4. Bee Research Laboratory, USDA-ARS, Beltsville, MD 20705, USA.
5. Department of Ecology and Evolutionary Biology, University of Arizona,
Tucson, AZ 85721, USA.
6. Department of Plant Pathology, The Pennsylvania State University,
University Park, PA 16802, USA.
7. The Center for Insect Science, University of Arizona, Tucson, AZ 85721, USA.
8. Department of Entomology, The Pennsylvania State University, 501 ASI
building, University Park, PA 16802, USA.; The Pennsylvania Department
of Agriculture, Bureau of Plant Industry - Apiculture, Harrisburg, PA 17110, USA.
9. 454 Life Sciences, Branford, CT 06405, USA.

In colony collapse disorder (CCD), honey bee colonies inexplicably lose their workers. CCD has resulted in a loss of 50 to 90% of colonies in beekeeping operations across the United States. The observation that irradiated combs from affected colonies can be repopulated with naive bees suggests that infection may contribute to CCD. We used an unbiased metagenomic approach to survey microflora in CCD hives, normal hives, and imported royal jelly. Candidate pathogens were screened for significance of association with CCD by examination of samples collected from several sites over a period of 3 years. One organism, Israeli acute paralysis virus of bees (IAPV), was strongly correlated with CCD.

 

Virus Is Newest Suspected Bee-Killer

WASHINGTON, Sept. 6, 2007(AP) Scientific sleuths have a new suspect for what's been killing billions of honeybees: a virus previously unknown in the United States.

The scientists report using a novel genetic technique and old-fashioned statistics to identify Israeli acute paralysis virus as the latest potential culprit in the widespread deaths of worker bees, a phenomenon known as colony collapse disorder.

Next up are attempts to infect honeybees with the newfound virus to see
if it's indeed a killer.

"At least we have a lead now we can begin to follow. We can use it as a marker and we can use it to investigate whether it does in fact cause disease," said Dr. W. Ian Lipkin, a Columbia University epidemiologist and co-author of the study. Details appear this week in Science Express, the online edition of the journal Science.

Experts stressed that parasitic mites, pesticides and poor nutrition all remain in the line up of suspects, as does the stress of travel. Beekeepers shuffle bees around the nation throughout the year so they can pollinate crops as they come into bloom. The newfound virus may prove to have added nothing more than insult to the injuries bees already suffer, said several experts unconnected to the study.

"This may be a piece or a couple of pieces of the puzzle, but I certainly don't think it is the whole thing," said Jerry Hayes, chief of the apiary section of the Florida department of agriculture.

Still, surveys of honeybees from decimated colonies turned up traces of the virus nearly every time; bees untouched by the phenomenon were virtually free of it. That means finding the virus should be a red flag that a hive is at risk and merits being quarantined, scientists said.

"The authors themselves recognize it's not a slam dunk, it's correlative. But it's certainly more than a smoking gun - more like a smoking arsenal. It's very compelling," said May Berenbaum, a University of Illinois at Urbana-Champaign entomologist.

The mysterious deaths have struck between 50 percent and 90 percent of commercial honeybee hives in the United States, sowing fears about the effects on the more than 90 crops that rely on bees to pollinate them.

Scientists previously have found blasting emptied hives with radiation apparently kills whatever infectious agent that causes the disorder. That has focused their attention on viruses, bacteria and the like, to the exclusion of other non-infectious phenomena, like cell phone interference, also proposed as culprits.

The earliest reports of colony collapse disorder date to 2004, the same year the virus was first described by Israeli virologist Ilan Sela. That also was the year U.S. beekeepers began importing bees from Australia - a practice that had been banned by the Honeybee Act of 1922.

Now, Australia is being eyed as a potential source of the virus. That could turn out to be an ironic twist, since the Australian imports were meant to bolster, not further damage, U.S. bee populations devastated by another scourge, the varroa mite. Meanwhile, officials are discussing reinstating the ban, said the Agriculture Department's top bee scientist, Jeff Pettis.

In the new study, a team of nearly two dozen scientists used the genetic sequencing equivalent of a dragnet to round up suspects. The technique, called pyrosequencing, generates a list of the full repertoire of genes in bees they examined from U.S. hives and directly imported from Australia.

By separating out the bee genes and then comparing the leftover genetic sequences to others detailed in public databases - a move akin to running a suspect's fingerprints - the scientists could pick out every fungus, bacterium, parasite and virus harboured by the bees.

They then looked for each pathogen in bees collected from normal hives and others affected by colony collapse disorder. That statistical comparison showed Israeli acute paralysis virus was strongly associated with the disorder.

The technique is a model for investigating outbreaks of infectious diseases in people too, since it can rapidly pinpoint likely causes, Lipkin said.

Sela, a Hebrew University of Jerusalem professor, said he will collaborate with U.S. scientists on studying how and why the bee virus may be fatal. Preliminary research shows some bees can integrate genetic information from the virus into their own genomes, apparently giving them resistance, Sela said in a telephone interview. Sela added that about 30 percent of the bees he's examined had done so.

Those naturally "transgenic" honeybees theoretically could be propagated to create stocks of virus-resistant insects, Lipkin said.

Acute bee paralysis virus causes paralysis in bees (Apis mellifera)

Viral diseases of honeybees are a major concern in apiculture, causing serious colony losses worldwide.

Paralysis, a minor disease of adult honey bees, is usually associated with filterable viruses. Two different viruses, chronic bee paralysis virus (CBPV) and acute bee paralysis virus (ABPV), have been isolated from paralytic bees. Other suspected causes of paralysis include pollen and nectar from such plants as buttercup, rhododendron, laurel, and some species of basswood; deficient pollen during brood rearing in the early spring; and consumption of stored fermented pollen.

Bees affected by this disease tremble uncontrollably and are unable to fly. In addition, they lose the hair from their bodies and have a dark, shiny, or greasy appearance. Paralytic bees are submissive to attack. When paralysis is serious, large numbers of afflicted bees can be found at the colony entrance, crawling up the sides of the hive and blades of grass, and tumbling to the ground. Healthy bees often tug at infected bees in an effort to drive them away from the hive. Affected bees also may be found on top bars or frames next to the hive cover with wings extended.

ABPV is a virus that effects mainly the honeybee ( Apis mellifera). ABPV has also been found in bumblebees and is the only bee virus known to have a natural alternate host . This virus spreads by way of salivary gland secretions of adult bees and in food stores to which these secretions are added. In Europe and North America, ABPV has been shown to kill adult bees and bee larvae in colonies infested with the mite Varroa Jacobsoni. The mite damages bee tissues and, in so doing, may act as a vector, releasing viral particles into the hemolymph. The biology of bee viral diseases, their relationship with mites, and their effects on bees are poorly understood. Analysis of the complete genome sequence of Acute Bee Paralysis Virus will provide a better understanding of the relationship among viruses, mites and colony decline.

The genome sequencing project has stated that the overall genome structure of ABPV showed similarities to those of Drosophila C virus, Plautia stali intestine virus, Rhopalosiphum padi virus, and Himetobi P virus, which have been classified into a novel group of picorna-like insect-infecting RNA viruses called cricket paralysis-like viruses. It is suggested that ABPV belongs to the cricket paralysis-like viruses.

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