"For the most part, they just disappeared," said Florida beekeeper Dave Hackenberg, who was among the first to note the losses. "The boxes were full of honey. That was the mysterious thing. Usually other bees will rob those hives out. But nothing had happened."
Researchers now think the foraging bees are too weak to return to their hives.
DeRisi and UCSF's Don Ganem, who normally look for the causes of human diseases, were brought into the bee search by virologist Evan W. Skowronski of the U.S. Army's Edgewood Chemical Biological Center in Maryland.
Dr. Charles Wick of the center had used a new system of genetic analysis to identify pathogens in ground-up bee samples from California. He found several viruses, including members of a recently identified genus called iflaviruses.
It is not known whether these small, RNA-containing viruses, which infect the Varroa mite, are pathogenic to bees.
Skowronski forwarded the samples to DeRisi, who also found evidence of the viruses, along with genetic material from \o7N. \f7\o7ceranae\f7.
"There was a lot of stuff from \o7Nosema\f7, about 25% of the total," Skowronski said. "That meant there was more than there was bee RNA. That leads me to believe that the bee died from that particular pathogen."
If \o7N. ceranae\f7 does play a role in Colony Collapse Disorder, there may be some hope for beekeepers.
A closely related parasite called \o7Nosema apis\f7, which also affects bees, can be controlled by the antibiotic fumagillin, and there is some evidence that it will work on \o7N. ceranae \f7as well.
jia-rui.chong@latimes.com
thomas.maugh@latimes.com
