Diagnostics

Gene sequencing identifies virus as possible cause of honeybee catastrophe

1 October 2007

Researchers at Columbia University, in collaboration with 454 Life Sciences, a Roche company, have identified a virus implicated in the deaths of millions of honeybee colonies using the company's genome sequencer system.

The findings explain how foreign organisms living in and among the bees were identified by reading sequences of DNA isolated from the bee colonies.

Dr. Ian Lipkin, Professor of Epidemiology at Columbia University's Mailman School of Public Health, and colleagues sequenced DNA and RNA samples that were extracted from collapsing and healthy bee colonies in search of any pathogen responsible for the collapse. The study was published in the online edition of Science.

The research identified five major bacterial groups, four lineages of fungi and seven types of viruses. While most of the foreign organisms were found in both the collapsed and healthy bee colonies, one virus, Israeli Acute Paralysis Virus (IAPV), was found only in the collapsed colonies.

As the researchers reported in Science: "We have not proven a causal relationship between any infectious agent and CCD; nonetheless, the prevalence of IAPV sequences in CCD operations, as well as the temporal and geographic overlap of CCD and importation of IAPV infected bees, indicate that IAPV is a significant marker for CCD."

"Unbiased 454 Sequencing technology enabled us to rapidly assemble a comprehensive inventory of microflora in colony collapse disorder (CCD) and non-CCD populations, and provided the sequence information needed to identify candidate pathogens," stated Dr. Lipkin. "We view this work as a model for investigating epidemics of unexplained infectious disease."

Bees play an integral role in the world food supply and are essential for the pollination of more than 90 fruit and vegetable crops worldwide. The economic value of these agricultural products is placed at more than $14.6 billion in the United States alone. In CCD, honeybee colonies inexplicably lose all of their worker bees. CCD has resulted in a loss of 50% to 90% of colonies in beekeeping operations across the United States. The observation that irradiated honeycombs from affected colonies could be repopulated with healthy bees, while non-sterilized combs could not, suggested an infectious basis for CCD. Suspected pathogens were screened for association with CCD by examination of samples collected from several sites over a period of three years.

"We are very pleased to see our technology applied to solve real-world problems. We are hopeful this latest research will help eliminate the threat of CCD to global agriculture" said Christopher McLeod, president of 454 Life Sciences. "The chief advantage of 454 Sequencing technology is how it quickly enables researchers to identify the organisms present in complex environments without any advance knowledge of the sample."

CCD was first reported in the fall of 2006 in the Unites States. Since then, CCD has been reported in Germany, Switzerland, Spain, Portugal, Italy and Greece. A recent survey of 13 states by the Apiary Inspectors of America showed that over a quarter of U.S. beekeepers have lost, on average, half of their bee colonies between September 2006 and March 2007.

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