Here is an excerpt taken from an article published on msncbc.com science page 3/15/2011
by Wynne Parry Live Science Senior Writer for MSNBC
Titled Big Mystery Surrounds Bees Tiny Foe
The mysterious disappearances of honey bees began in the fall of 2006 in Florida and spread. Beekeepers found their colonies suddenly empty, except for the queen and a few workers, with no traces of dead bees. In the years since it was named, colony collapse disorder (CCD) has continued to devastate the insects crucial to pollinating crops in North America.
Jerry Bromenshenk, a research professor at the University of Montana, and colleagues have linked vanishing colonies in North America with a virus-fungal tag team. The virus is insect iridescent virus, named for the effect it creates in infected tissues, and the fungi is Nosema ceranae, a microsporidian. In a study published in October 2010 in the journal PLoS ONE, the team described finding this combo in bees from failing colonies, and by testing both pathogens in bees, they found that together, they were more lethal than if they infected bees separately.
Until 2007, N. ceranae infections had only been reported in Asian honey bees, not among the Western honey bees used in North America and elsewhere. The microsporidian has now been discovered in old samples going back to the 1990s, but it’s possible the pathogen has been around even longer, according to Bromenshenk and colleague Colin Henderson, of The University of Montana College of Technology.
N. ceranae is now found nearly everywhere honey bees are kept, Bromenshenk said. He cautioned, however, that CCD does not appear to be behind most problems with honey bees elsewhere in the world.