a survey our team conducted in the spring of 2007 revealed that a fourth of U.S. beekeepers had suffered similar losses and that more than 30 percent of all colonies had died. The next winter the die-off resumed and expanded, hitting 36 percent of U.S. beekeepers. Reports of large losses also surfaced from Australia, Brazil, Canada, China, Europe and other regions. More recent data are not available yet, but some beekeepers say they have seen their colonies collapse this winter, too.
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Our collaboration has ruled out many potential causes for CCD and found many possible contributing factors. But no single culprit has been identified. Bees suffering from CCD tend to be infested with multiple pathogens, including a newly discovered virus, but these infections seem secondary or opportunistic much the way pneumonia kills a patient with AIDS. The picture now emerging is of a complex condition that can be triggered by different combinations of causes. There may be no easy remedy to CCD. It may require taking better care of the environment and making long-term changes to our beekeeping and agricultural practices.