(NaturalNews) A virus has been identified that is strongly associated with colony collapse disorder in the United States, according to a new study conducted by researchers from Pennsylvania State University, Columbia University, the U.S. Department of Agriculture (USDA) and a number of other institutions and published in the journal "Science."
In colony collapse disorder, the worker bees in a hive die off en masse without apparent reason, even though there are still plentiful supplies of food as well as a queen and other adult bees. The disorder first surfaced in the United States in 2004, and was formally recognized in 2006. In the winter of 2006-2007, it led to the destruction of 23 percent of the beehives in the United States.
Researchers examined the genes of bees from colonies that had and had not collapsed, comparing them against the mapped honeybee genome and searching for modifications caused by bacteria or viruses. Twenty-five of the 30 collapsed colonies showed evidence of exposure to Israeli acute paralysis virus (IAPV), while only one of the 21 unaffected colonies did.
"The only candidate which was left standing at the end of this very rigorous process was IAPV," said researcher W. Ian Lipkin.
"This is a major finding," he said. "What we have at present is a marker. We do not think IAPV alone is causing this disease."
Other factors that the researchers believe may be involved in colony collapse are varroa mites and pesticides, both of which may lower bees' resistance to IAPV. The researchers said that they found no evidence that cellular phone signals were involved in colony collapse disorder.
Researchers believe that IAPV may have been introduced into the United States by Australian honeybees. Since there are no varroa mites in Australia, the virus may not have triggered colony collapse there.
Colony collapse has occurred in other countries, but nowhere on the same scale as the United States.
USDA researchers are now planning to inject healthy honeybee colonies with IAPV to see if it causes massive die off.