Stan Sandler and Murray McGregor make some good comments on Nosema in honey
bees.  But remember that, as with all diseases, and conditions of colonies
you don't know whether the bees have Nosema, or other organism, unless you
do some laboratory work.  Observations may suggest that the "condition" of a
colony(s) is not as it should be, but defining the condition or identifying
the malady can only be done by the laboratory.  (Even though Varroa can be
seen you don't know the level of infection until you conduct a survey.)
Anything else is mere conjecture.  Conjecture costs the beekeeping industry
hundreds of thousands of dollars each year in the US because the business
decision was not based upon laboratory work or doing a literature search.
Drs. Furgala and Mussen did the definitive work on Nosema years ago and
there has been some additional science since then.

You might read my article in the November 1999 Gleanings on Page 34 for
additional studies in Washington State.

Thanks

James C. Bach
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