How honeybee dies

U.S. bee colonies began to be infected with the fungus Nosema ceranae a few years before bee numbers began dropping.

A one-two punch by a gut parasite and viruses may help explain the mysterious decline in U.S. honeybees seen over the last four years.
Bees infected with both the fungal parasite Nosema ceranae and with any one of a handful of RNA viruses were much more likely to have come from hives on the decline than from healthy hives, researchers reported May 25 at a meeting of the American Society for Microbiology. U.S. bee colonies began to be infected with the fungus Nosema ceranae a few years before bee numbers began dropping.
The finding represents a new twist in a complex and multifaceted scientific problem, termed colony collapse disorder, made urgent by the continuing and severe losses suffered by U.S. beekeepers beginning in 2006. About a quarter of beekeepers have been affected, according to the Apiary Inspectors of America, an industry group. These beekeepers, including honey producers as well as many who lease out their bees to pollinate food crops, have reported losing between 30 and 90 percent of their hives. The latest nationwide survey, of 2009-2010 winter losses, revealed more than 30 percent of hives were lost for a variety of reasons.

Source: Science news