Scientists are reporting their first solid lead in the urgent search for the cause of colony collapse disorder, the mysterious disappearance of billions of honeybees across the nation.
The suspect is a virus, identified by a novel technology designed to find the cause of human epidemics. The virus may have been introduced with bee colonies imported to the United States from Australia in 2004. That was when an 80-year- old bee import ban - designed to prevent introduction of disease - was lifted to meet soaring demand for crop pollination.
Modern agriculture is critically dependent on commercial bee operations. Without them, fruits, nuts and vegetables would be deformed or never form at all, cutting yields.
The identification of Israeli acute paralytic virus as a possible cause of CCD was reported yesterday in the online journal Sciencexpress, published by the American Association for the Advancement of Science.
Scientists stressed they haven't proved IAPV is at fault, only that it is closely associated with colony collapse. If it is the cause, they don't know whether it triggers CCD directly or in combination with other infections, parasites, bad weather, poor nutrition or pesticides.
"I hope no one goes away with the idea we've solved the problem. We still have a great deal of work to do," said Jeffery Pettis, research leader at the Bee Research Laboratory at the U.S. Agricultural Research Service in Beltsville.
If IAPV is found guilty, a cure may remain elusive.
"There are some anti-viral materials, but they are so expensive I don't think we will be looking at any kind of treatment," said Dr. W. Ian Lipkin, an epidemiologist at the Mailman School of Public Health at Columbia University.
Beekeepers may have no options other than to sterilize their hives with radiation, then redouble their efforts to keep their bees well-nourished and free of mites and other infections that may lower their resistance to IAPV.
In the meantime, U.S. Agriculture Department officials and their Australian counterparts are discussing a possible halt to the import of Australian bees until the mystery is solved. The USDA is also "making a statement to beekeepers ... not to use royal jelly [used to feed and produce queen bees] from outside the country," Pettis said.
Some royal jelly, imported from China for human consumption and cosmetics, was found to contain IAPV.
Commercial bee operations pollinate more than 100 food crops. Every year, beekeepers truck millions of hives around the country, moving with the seasons to pollinate blueberries in Maine, citrus groves in Florida and pumpkins in Pennsylvania. They're also vital to forage crops, such as alfalfa, clover and pasture grasses.
California's $2 billion almond industry is entirely dependent on commercial pollination. In a two-month period every year, almonds alone require the services of half the nation's remaining 2.5 million bee colonies.
Beekeepers have always suffered periodic losses and die-offs. Many operators have quit, reducing the number of commercial hives from 5 million in the 1940s and 1950s to half that today.
So beekeepers were alarmed in October when their bees began to disappear in large numbers. Through winter, an estimated 23 percent of the nation's commercial operators lost an average of 45 percent of their bees. Looking back, researchers found evidence the die-offs may have begun in 2004.
Similar reports have come from European countries and Taiwan, and all but 14 U.S. states. CCD has not yet been formally identified in Maryland, but some commercial beekeepers have reported losses that look much like it.
With other diseases, bees are found dead in and around the hives. With CCD, the worker bees just vanish, leaving the queen and a few attendants, with plenty of food and young still in the hive.
When researchers discovered they could successfully repopulate affected hives after sterilizing them with radiation, they knew they were dealing with a disease, rather than the effects of pesticides or other environmental factors.
IAPV was first described in 2004 in Israel. Infected honeybees exhibited shivering wings, followed by progressive paralysis and death.
Normally, identifying the pathogen would require a time-consuming process of isolating and identifying a list of individual pathogens.
Instead, scientists from Penn State, the USDA, Columbia University, the National Institutes of Health, the University of Arizona, the Pennsylvania Agriculture Department and 454 Life Sciences, a Connecticut company, joined forces to try something different.
Using tissue samples gathered from CCD-affected hives and healthy hives across the country, as well as bees from Australia and royal jelly from China, they conducted a "metagenomic survey."
The samples were separated into "presumed CCD-positive" and "presumed CCD-negative" batches, and submitted for wholesale genetic sequencing. The results, after subtracting the bee's own genome, were then compared to databanks containing genetic codes from known bacteria, viruses, parasites, fungi and other pathogens.
The goal was to identify, all at once, the entire microbiological zoo inside the bees and then look for those most exclusively linked to CCD-affected hives.
The bee researchers identified eight kinds of bacteria, which probably perform essential functions in the bee's gut; four types of fungi; seven viruses; plus mites and the protozoan trypanosome.
Most were found in both the CCD-affected and healthy bees. The only one associated exclusively with the CCD-affected bees was IAPV. The virus was also present in the bees imported from Australia and in two of four royal jelly containers from China.
But while IAPV seems to be associated with CCD, scientists still lack proof that it's the cause.
"Now comes the hard work," Pettis said, "to try and see if we can re-create CCD symptoms" in previously healthy bees by infecting them with purified IAPV.
At stake are billions of dollars in agricultural productivity and the livelihoods of many commercial beekeepers. "I won't kid you," Pettis said, "these are anxious times for a lot of people. I wish we had a little more time."