Link Between Virus and Bee Collapse

A team led by scientists from the U.S. Department of Agriculture's Agricultural Research Service, Pennsylvania State University, and Columbia University has found an association between colony collapse disorder (CCD) in honey bees and a honey bee virus called Israeli acute paralysis virus, according to a paper published in the journal Science.  Genetic screening of honey bees collected from 30 colonies with CCD and 21 colonies with no CCD from four locations in the United States allowed researchers to identify pathogens to which the sampled honey bees had been exposed.  In total, the honey bees (both CCD and non-CCD honey bees) were found to harbor six symbiotic types of bacteria and eight bacterial groups, 81 fungi from four lineages, and seven viruses.

The search for potential pathogens was done using a new means of sequencing the genetic material from the healthy and unhealthy bees.  This technology, termed high-throughput sequencing, allows for an unbiased look at DNA from all the organisms, bacteria, fungi and viruses present in the bees.  Then the DNA sequences are searched against known genomic libraries for best matches.  This gives a very precise picture of the organisms present, at least to the family or genus level.  Often specific species can be identified, and unknown organisms can be cataloged for further study.

The only pathogen found in almost all samples from honey bee colonies with CCD, but not in non-CCD colonies, was the Israeli acute paralysis virus (IAPV), a dicistrovirus that can be transmitted by the Varroa mite.  It was found in 96 percent of the CCD-bee samples.  This is the first report of IAPV in the United States.  This virus was initially identified in honey bee colonies in Israel in 2002, where the honey bees exhibited unusual behavior, such as twitching wings outside the hive and a loss of worker bee populations.  Although IAPV has not yet been formally accepted as a separate species, it is a close relative of Kashmir bee virus, which has been previously found in the United States.  More information about CCD can be found at: www.ars.usda.gov/is/br/ccd/  (USDA ARS, 9/6/07).