Genetic Survey Finds Association Between CCD and
Virus By Kim
Kaplan September 6, 2007
WASHINGTON, Sept. 6A team led by scientists from the
U.S. Department of Agriculture's
Agricultural Research Service (ARS),
Pennsylvania State University (PSU), and
Columbia University (CU) 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 this
S. Pettis, research leader of the agency's
Research Laboratory in Beltsville, Md.; Diana L. Cox-Foster, a professor in
the PSU Department of Entomology; and W.
Ian Lipkin, director of the Center for Infection and
Immunity at the Columbia
University Mailman School of Public Health, led the team that did genetic
screening of honey bees collected from 30 colonies with CCD and 21 colonies
with no CCD from four locations in the United States.
The genetic screening allowed the researchers to identify pathogens to
which the sampled honey bees had been exposed. In total, the honey
beesboth CCD and non-CCD honey beeswere 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 organismsif presentcan also be catalogued for further
study. The sequencing work was led by Michael Egholm, vice president of
454 Life Sciences Corp. of Branford, Conn.,
followed by a large group effort to further identify specific groups of
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 96.1 percent of the CCD-bee samples.
This is the first report of IAPV in the United States. IAPV 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. 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.
"This does not identify IAPV as the cause of CCD," said Pettis. "What
we have found is strictly a strong correlation of the appearance of IAPV and
CCD together. We have not proven a cause-and-effect connection."
Even if IAPV proves to be a cause of CCD, there may also be other
contributing factorswhich researchers are pursuingthat stress the
bee colony and allow the virus to replicate.
The next step is exposing healthy hives to IAPV and seeing if CCD
CCD became a matter of concern in the winter of 2006-2007 when some
beekeepers began reporting losses of 30 to 90 percent of their hives. While
colony losses are not unexpected during winter weather, the magnitude of loss
suffered by some beekeepers was highly unusual.
The main symptom is finding no or a low number of adult honey bees
present with no dead honey bees in the hive. Often there is still honey in the
hive and immature bees (brood) are present.
Pollination is a critical element in agriculture, as honey bees
pollinate more than 130 crops in the United States and add $15 billion in crop
value annually. There were enough honey bees to provide pollination for U.S.
agriculture this year, but beekeepers could face a serious problem next year
and beyond if CCD becomes more widespread and no treatment is developed.
More information about CCD can be found at
ARS is the U.S. Department of
Agriculture's chief scientific research agency.