Does anyone really doubt that the hives in which nosema afflicted
colonies have lived and even died are covered with spores?  One
doesn't need to see the spores to know that they are there any more
than one needs to see dandelion seeds to be certain if dandelions will
come up in a field the next year after a heavy dandelion bloom.
Finding nosema infection in the bees is indication that they are sick
and leaving spores everywhere.

Nosema was one of the first infectious diseases to be studied by
Pasteur. That the spores are everywhere is evidenced by the fact that
the only way Pasteur could raise healthy moths was to segregate the
eggs into a disease free environment. The disease is not transmitted
via the egg. Unfortunately this is no help in treating bees with
nosema, as the larvae require the care of the bees. That is why the
disease must be treated in the bees themselves.

Sterilizing comb is just a precaution against reinfection, which
probably is not even worth the trouble. If you are feeding fumagillin
the bees will be protected from reinfection from combs. Sterilizing
the combs would only be worthwhile if you were assured that you
restocked with bees that were nosema free and that they weren't going
to pick it up soon from somebody else's sick bees. Or, if you had in
mind avoiding antibiotics at all costs, acetic acid is certainly an
intelligent alternative, though expect it to do nothing to kill the
nosema in the bees.

> In 1865, the French government commissioned Pasteur to investigate pébrine disease [nosema bombycis], which was killing silkworms and devastating the national silk industry. After three years, Pasteur discovered that pébrine was caused by a microorganism, and showed that disease could be prevented if healthy worms and eggs were separated from sick worms and contaminated materials.

Timeline: Louis Pasteur, 1822–1895 By Sheng Wang
http://www.medhunters.com/articles/timelineLouisPasteur.html

-- 
Peter L Borst
Danby, NY  USA
www.people.cornell.edu/pages/plb6

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