I'll agree with Yoon (as I so often do) that Nosema ceranae
is pretty much a non-issue, even though it may have seemed
scary a few months ago.

Let me explain.  What I type below is from memory, but
I have a pretty good one.  At the USDA-ARS CCD meeting that
was held in Beltsville MD, we got a mini-presentation on
why Nosema ceranae was NOT a likely suspect as a proximate
cause of CCD:

1) It has been in the USA for years.

2) Nearly all the Nosema we have all seen for roughly
   the past decade or so turns out to have been either:

2a) Nosema ceranae itself

2b) A variant/mutation of Nosema ceranae that seems to
    be much more "successful" than the original Nosema
    ceranae in infesting European Honey Bees. 

Eric Mussen offered that he is (now) very sure that he saw
Nosema ceranae years ago, but at the time, he dismissed
his own "speculation" at the time.

When several sites who keep samples for long periods
looked at their "library" samples of Nosema, they got 
a surprise. They found that it has all been Nosema 
ceranae for quite some time. 	They were hard pressed
to find an authentic example of "traditional" Nosema apis.

So, we are left with one or more of the following:

a) Nosema ceranae is not the rapid and brutal killer
   of EHB it was thought to be

b) Nosema ceranae somehow changed somewhere along the 
   way from Asia to here, and became much less virulent
   a killer of EHB as a result.

c) We are looking at a hitherto unknown variant of
   Nosema, that may LOOK like Nosema ceranae, but
   is nowhere near as deadly to EHB colonies it infests
   as Nosema ceranae was said to be.

And the best news of all - Fumagillin stops it cold, just
like it stopped "traditional Nosema" cold.

Note that the appearance of the two different "paramecia" 
(ok, ok, "microsporidia" under the new classification scheme...)
that one sees under a microscope when examining a bee 
midgut are very very very similar.  Everyone missed it, or
shrugged off the physical differences.  It was only when
doing fancy analysis that the difference was detected.
(I don't remember what kind of test revealed the difference.)

The above is what I heard at the meeting in Beltsville.

Now, I get to comment in my own voice:

There is an obvious, yet unanswered question.

How did it get here?  
In live bees, of course.
That's the best way to get a pest or disease of bees
across an ocean or two.

How did live bees get here from Asia, when Asia may not
export bees to the USA or Canada?  To answer that question,
my guess would be that you may want to look at how many ships 
move between Asia and certain countries that Canada turned to 
for package bees when it closed its border to bees from the 
USA over a decade ago.  

Canada was still welcome during that time to export bees to
the USA, and many Northern beekeepers liked the "Canadian"
stock, thinking that they were somehow able to survive winters
better (evincing a complete lack of understanding of the
concept of "regression to the mean", and holding some
perhaps confused beliefs reminisient of Lysenkoism).

Naw, that couldn't be it - it had to be the bee disease 
gremlins, who travel in the wheel wells of 747s and 767s.  :)

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