September 6, 2007
A 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 week.
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 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 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."
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.1
IAPV was also found in apparently healthy bees from Australia, which could be a significant clue to the origin of the virus in North America since the U.S. began importing bees from Australia in 2004.
"..data does suggest that chemical pesticides could be helping to stress the bees or act as a potential trigger of specific viruses." said Cox-Foster.
Disappearing bees have been reported in 27 states so far and damaged nearly one-quarter of all beekeeping operations in the U.S. last winter.
Dr. Pettis said that even if the virus was involved, it was likely that more than one factor had to align for a hive to collapse, with another possible influence being poor nutrition. Another factor could be the stress that comes from the increasingly industrial-style beekeeping operations in the United States, in which truckloads of hives crisscross the country to pollinate California almonds or Florida orchards each season.
Israeli acute paralysis virus (IAPV) : first identified by scientists in Israel. It appears to exist in many parts of the world.
Ref 1 : US Dept Agriculture