Newly Discovered Virus Linked to Honeybee Dieoff

WASHINGTON — A newly discovered virus, possibly imported from China or Australia, has been linked to the baffling plague that decimated thousands of U.S. honeybee colonies last year, scientists revealed Thursday.

The virus, known as Israeli Acute Paralysis Virus, was found in tissues of bees from affected hives, but rarely in those from healthy hives, researchers said.

It is also present in honeybees from Australia, imported into the United States for the first time in 2004, and in "royal jelly," a honeybee product that is imported from China.

The die-offs occur when adult worker bees fail to return to hives, leaving larvae and a few adult bees inside to slowly perish. An estimated 23 percent of American beekeeping operations suffered from colony collapse disorder during the winter of 2006-2007.

A group of scientists from several universities and the U.S. Department of Agriculture described details of the link between colony collapse events and the virus, called IAPV, in a paper published online Thursday by the journal Science.

They also found that the virus can be spread from bee to bee by a mite called varroa that has plagued U.S. honeybees for about 20 years.

They emphasized during a news conference that the discovery does not definitively identify the IAPV virus as the cause of the mysterious colony collapse disorder, which was first discovered in Florida last November.

"I hope no one goes away with the idea that we've actually solved the problem," said Jeff Pettis, a U. S. Department of Agriculture entomologist. "We still have a great deal of research to do to resolve why bees are dying."

Scientists are now trying to infect healthy hives with the virus to see if this will cause colonies to collapse, he said.

Pettis and other authors of the report speculated that colony collapse events are caused by a combination of factors, possibly including infection by the IAPV virus.

They said other factors still being studied include insecticides, parasites, other microbes or just the plain stress of poor diet and hard work often imposed on commercial honeybees.

Such factors could suppress bees' immune systems and make them more susceptible to the virus, they said.

On the other hand, if some other cause is behind the colony collapse disorder, it might also leave bees less able to ward off the IAPV virus and thereby account for the association, they said.

About 15 of the country's largest beekeepers were briefed on the research Thursday afternoon in a conference call with authors of the study.

"Our main concern is that people, including members of Congress, will read about this and decide the problem is solved," said Troy Fore of Jesup, Ga., executive director of the American Beekeeping Federation. "It's not solved, and we need this research to continue."

Fore said some beekeepers are considering calling on USDA to ban further Australian imports until the cause of colony collapse disorder is finally solved.

In addition to more than $150 million worth of honey a year, U.S. bees perform vital pollination functions in many crops, ranging from Florida citrus to Maine blueberries and California almonds.

In fact, millions of bees are necessary to pollinate California's huge almond orchards, and pressure from almond growers was largely responsible for a change in U.S. law to permit importing bees from Australia.

To screen bees for pathogens, the scientists used new technologies that can scan biological samples and isolate genetic sequences. These sequences are then compared to vast "libraries" of genetic code to identify the animals, plants or microbes they come from.

Scientists scanned specimens of bee tissue from healthy U.S. hives, diseased hives and healthy Australian bees. All of the diseased U.S. hives either contained Australian bees or had intermingled with beekeeping operations that had the imported bees.

Royal jelly, a substance produced by bees and fed to all larvae, also was sampled.

In the United States, the substance is imported from China for use in health foods and cosmetics. Beekeepers often buy the imported material and use it to supplement insects' feed, scientists said.

After eliminating the honeybees' own genetic sequences, the comparisons found genetic matches to numerous familiar species of bacteria, fungus, virus and parasitic mites.

They also revealed two viruses not seen before in U.S. bees: IAPV and Kashmir bee virus, which are related, the researchers reported.

IAPV was found in all samples taken from hives that had suffered colony collapse disorder, in Australian bees and two of four samples of royal jelly. The Kashmir virus was found in colony collapse samples, in Australian bees but not in royal jelly.

The Kashmir virus was also found in samples from healthy U.S. hives — but, except for a single exception, IAPV was not found in any samples taken from hives believed to be healthy, the researchers said.

IAPV was first identified in 2004 in Israel, where infected bees first developed "shivering" wings then became paralyzed and died.

These symptoms have not been reported in U.S. colony collapse disorder or in Australian bees.

However, the scientists said differences in bee environments could cause the virus to be deadly in one area and not in another. For example, Australia does not have the varroa mite.