Here's the abstract (permitted by fair use, I believe):

Honeybee colony collapse is a sanitary and ecological worldwide problem. The features of this syndrome are an unexplained disappearance of adult bees, a lack of brood attention, reduced colony strength, and heavy winter mortality without any previous evident pathological disturbances. To date there has not been a consensus about its origins. This report describes the clinical features of two professional bee-keepers affecting by this syndrome. Anamnesis, clinical examination and analyses support that the depopulation in both cases was due to the infection by Nosema ceranae (Microsporidia), an emerging pathogen of Apis mellifera. No other significant pathogens or pesticides (neonicotinoids) were detected and the bees had not been foraging in corn or sunflower crops. The treatment with fumagillin avoided the loss of surviving weak colonies. This is the first case report of honeybee colony collapse due to N. ceranae in professional apiaries in field conditions reported worldwide.

Obviously treating every colony in the world with fumagillin would not be a good idea - too expensive, and certain to lead to resistance. But knowing the cause makes it much more likely that good practices can reduce the incidence, and the fumagillin makes a good back up if hygiene fails.

Thought you all would enjoy getting some good news on this lovely spring day! (Lovely here at least - hope most of you are also enjoying some true spring).

And some eye candy from UCSD:

(UPDATE 1&2)

Since this is getting visibility, here are some more resources:

Info on CCD from Mid-Atlantic Apiculture Research and Extension at Penn State, including a powerpoint if you want to present to a group

Map (pdf) of affected states

Russians have developed strains resistant to varroa mites, another baddy

A comment with a great link to a Scientific American article

A comment about encouraging local pollinators

Help count bees!

(update 3)

An excursus on Koch's postulates

How do we know whether an organism causes a disease? Since the nineteenth century, Koch's postulates have helped frame our searches: Koch's postulates are: 1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy animals.

2. The microorganism must be isolated from a diseased organism and grown in pure culture.

3. The cultured microorganism should cause disease when introduced into a healthy organism.

4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent. (from Wikipedia) But as the article suggests, there are various reasons that each of these may not be able to be satisfied in a given case. In this instance, all the colonies examined in this study had Nosema, other causes were not present, and colonies were cured by treatments that eliminated the fungus. Koch would like to have seen Nosema introduced into new colonies and CCD resulting to be more confident of the link, but that may be impractical - it is impossible for a number of diseases that still have causes accepted for them. The evidence here seems good enough to say that a cause (note: not the cause) of CCD has been shown.

Update 4:

Great comment about honeybee genetics and how that may put them at greater risk than wild bees

Link here to a Salon article with lots of bee-y goodness

Update 5:

It appears that we have more bees now than in the past three years. The suggested explanation is that the apiarists affected by CCD either left or changed what they do with the bees. Things like feeding the bees when there's not much food or paying close attention to hygiene are all the sorts of things that can reduce vulnerability to infectious agents. Remember, the big drop in mortality for humans in Europe didn't come from medicine; it came from clean water and good sewage.

Organic beekeepers can also be affected by CCD, where it behaves like an infectious disease.