Beekeepers and scientists alike have been alarmed and puzzled by a mysterious phenomenon, known as colony collapse disorder (CCD), which has affected nearly one-third of US bee colonies over the past few years. Now, researchers believe a number of insect viruses that disrupt gene expression may be to blame. Researchers studied the genomes of healthy bees and bees that came from hives that had suffered from CCD and found that the sick bees exhibited genetic damage that could compromise protein production and cause the die-off(個体群の大量死)