Scientists from the U.S. Department of Agriculture's Agricultural Research Service (ARS) have found that the Israeli acute paralysis virus (IAPV), a virus recently shown to be associated with Colony Collapse Disorder (CCD) of honeybees, has been in the United States since at least 2002, according to a note published in the American Bee Journal.
Research entomologists Yanping (Judy) Chen and Jay D. Evans, both with the ARS Bee Research Laboratory here, conducted a detailed genetic screening of several hundred honey bees that had been collected between 2002 and 2007 from colonies in Maryland, Pennsylvania, California and Israel.
"Our study shows that, without question, IAPV has been in this country since at least 2002," said Chen. "This work challenges the idea that IAPV is a recent introduction from Australia."
Evans added, "Our study in no way rules IAPV out as a factor in CCD. We have always believed that CCD is a complex issue likely involving multiple elements. Research by several groups will now focus on understanding differences in virulence across strains of IAPV and on interactions with other stress factors."
IAPV showed a high degree of genetic diversity in the U.S., with distinct lineages in California, Maryland and Pennsylvania. The virus was found to be substantially different from the well-studied Kashmir Bee Virus.
IAPV, first described in Israel in 2002, came to national and international attention in September when university and ARS scientists, including Evans, showed a strong association between the presence of IAPV and CCD.
That first study also found IAPV in honeybees from Australia that had been imported into the United States, as well as in royal jelly imported from China. Australian bees began to be imported from Australia into the United States in 2005. Questions were raised about a connection between those imported bees and the appearance of IAPV in the United States. Beekeepers have sought out Australian imports of bees to replenish their hive populations.
ARS has begun several experiments to determine what factors may be most involved in CCD. Combinations of four areas are being examined: pathogens, parasites, environmental stresses, and bee management stresses such as poor nutrition.
CCD became a matter of concern in the winter of 2006-2007 when some beekeepers began reporting losses of 30 percent to 90 percent of their hives. While colony losses are not unexpected during winter weather, the magnitude and rapidity of loss suffered by some beekeepers was highly unusual.
The defining trait of CCD is a low number of adult honeybees present with few signs of dead honeybees in the hive. Often there is still honey in the hive and immature bees (brood) are present, indicating recent brood rearing.
Pollination is a critical element in agriculture, since honeybees pollinate more than 130 crops in the United States and add $15 billion in crop value annually. There were enough honeybees 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.