I also cannot help you with information about local Nosema problems in
your area or details about treatment and its effects.  The identification
method proposed by O.G. Marti is certainly a good one but it's a lot of
work if you want to screen a lot of bees for Nosema.  You can bypass the
grinding filtering and centrifuging by just quick killing bees (freezing
is probably the easiest method), dissecting out their midgut - the broad
section of their insestine - and examining a few drops of the midgut
contents under your microscope.  Heavy infections will also show up in
feces.  I have examined lots of field caught bumble bees for Nosema, and
spores are visible even at 200X magnification.  In addition, after you've
seen it a few times you'll probably be ably to note heavy infections just
by the milky colour of the midgut.  The only thing I know of that you could
confuse with Nosema are fungal spores, but they are much more variable in
size and shape than are Nosema spores.
 
			Jacqui Shykoff