Researchers think they have have identified one factor in the mysterious destruction of beehives across the United States and in some other countries. It is called the Israeli Acute Paralysis Virus, which scientists believe was recently introduced into the United States. As VOA's Jessica Berman reports, researchers are trying to learn more about the virus to stop its spread.
Starting in 2004, U.S. beekeepers began noticing that adult worker bees mysteriously disappeared from their hives without a trace, leaving honey and queen bees behind. The phenomenon was dubbed Colony Collapse Disorder because the hives died after being abandoned. A similar phenomenon was noted in Australia.
CCD has now affected between 50 and 90 percent of hives in the U.S. In addition to producing honey, bees are used by farmers to pollinate fruit and vegetable crops. Experts say the U.S. agriculture industry provides over 90 fruit and vegetable crops worldwide.
American researchers began looking for an infection agent when the problem became acute. Investigators say honey bees contain 18 different microbes in their abdomens.
Using a high tech sequencing technique to analyze the DNA of bees collected over the past three years from healthy and unhealthy U.S. and Australian hives, Israeli Acute Paralysis Virus stood out among some of the bees.
Researchers also tested what is called royal jelly, imported from China, as a possible lead. Royal jelly is secreted by worker bees to feed larvae in starting a new hive.
While scientists broke new ground in terms of analyzing diseases of insects, markers for Israeli Acute Paralysis Virus were found in both healthy and unhealthy beehives and in some of the royal jelly samples that were tested.
John Pettis is chief of bee research at the U.S. Department of Agriculture and co-author of the study published this week in the journal Science.
"At this point we only have an association. I think where we can go with this is to look at both historical samples in the U.S. prior to 2004 when we imported packaged bees from Australia and also to look at more worldwide distribution of IAPV to try to understand this story," he said.
Experts say IAPV was first discovered in Israel where infected bees developed shivering wings and became paralyzed before collapsing and dying outside the hive.
Reports of Colony Collapse Disorder in the United States could mark the first time the Israeli bee virus has been identified here, but how it got to the United States or at what point it became infectious, if at all, is still a mystery.
Researchers think that, because the virus has been found in both healthy and unhealthy bees, some other environmental factor, such as drought, may be needed to trigger the disorder.
Until now, there was speculation that Colony Collapse Disorder was caused when worker bees became disoriented by radio waves emitted by cell phone towers and then died, or because worker bees were pollinating genetically-modified crops.
Senior author Diana Cox-Foster of Pennsylvania State University says the study has pretty much ruled out those theories. In fact, she says genetically altered crops appear to be beneficial to bees.
"The evidence to date shows that bees feeding on pollen from transgenic corn have as good as survivorship or better survivorship than bees feeding on normal pollen," she said.
Researchers say the next step is to see whether they can cause Colony Collapse Disorder in the laboratory by infecting bees in healthy hives with Israeli Acute Paralysis Virus. That way, they may be able to come to a definite conclusion about the cause of the disease.