>>>> Actually, recent work shows that treating N. ceranae with fumagillin
makes it worse.
>>> That statement should have some qualifiers.
>> "The current application protocol for fumagillin may exacerbate N.
ceranae infection rather than suppress it"
> Note that they included the qualifier "may."
Why not look at the figures and tables - the empirical evidence itself?
The good news is that bees correctly dosed with Fumagillin had >>NO<<
detectable Nosema ceranae or apis in their midguts over the entire study
period. But bees fed only a miniscule dose of Fumagillin had higher Nosema
spore counts than even untreated bees.
But the study was yet another caged-bee study, and it did NOT cover the
obvious scenario that jumps to the mind of any beekeeper, where the bees
would be infected, given the proper dose, and then exposed to both
reinfection and lower doses of Fumagillin over time from a presumed storage
and later consumption of some fraction of the medication due to incorrect
deployment of the medicated feed.
Table 1 shows that the bees fed the correct dose of Fumagillin had spore
counts of "NA" ("below the detectable number"), and the notes for the table
explain that the numbers given are averages of the counts done from day one
to day 20. So, for both Nosema apis and Nosema ceranae, the correct dose
works very well at least initially, when there is no chance of reinfection.
Figure 1 shows only the data for the zero-dose controls, the 0.01x dose and
0.001x dose. So, for both Nosema apis and Nosema ceranae, one-100th and
one-1000th of the proper dose make for higher spore counts.
But widespread experience with Nosema apis in the 1990s and 2000s directly
contradicted the study's findings, as least the Nosema apis findings. A
single early-spring treatment with Fumagillin was a very effective control.
I even gave talks up and down the east coast about how Nosema apis was the
worst problem beekeepers faced, in that, if untreated, it kept hives from
thriving into robust massive colonies that could be split into fall nucs,
and kept colonies weak and thereby susceptible to all the other problems of
bees and beekeepers.
The abstract flatly states,"Fumagillin degrades or is diluted in hives over
the foraging season, exposing bees and the microsporidia to declining
concentrations of the drug." This seems to over-state the case for at least
Nosema apis, given the consensus about Nosema apis and one-shot effective
cures mentioned above, and the confirmation of that by the data.
The text of the paper says "Fumagillin persists inside hives [2] and
degrades over time" [14], referencing two papers cited at the end of this
message that I cannot read until I trudge down to the main branch of the NYC
Public Library at 34th St. (No, longer - NYPL has no "Apidologie"
subscription.)
So, the essential questions become these:
1) "Will bees fed Fumagillin in thin syurp in early spring consume all of it
within 20 days or so?"
2) "Is anyone so foolish as to treat with Fumagillin during the 'foraging
season'?"
(The paper does note "Fumagillin treatment is prohibited during the
foraging season")
3) Can residues remain to give any bees 1/100th or 1/1000th of the dose for
an extended period like 20 days?
4) Once treated, can both nosema reinfection and these sorts of residues
coincide?
5) Are the higher spore counts of Nosema MEDICALLY worse for the bees than
the spore counts for the untreated bees?
6) Is Nosema even worth treating at all? There is some evidence that says
"no".
7) If I lined up a row of microscopes with slides from the same infected
sample, would any two people give me similar counts?
All the questions hinge on what the papers cited below say about the actual
persistence and levels of Fumagillin in beehives, assuming that they only
looked at examples of proper husbandry, where medications are not fed during
"the foraging season".
2. Higes M, Nozal MJ, Alvaro A, Barrios L, Meana A, et al. (2011) "The
stability and effectiveness of Fumagillin in controlling Nosema ceranae
(Microsporidia) infection in honey bees (Apis mellifera) under laboratory
and field conditions". Apidologie 42: 364-377. doi:
10.1007/s13592-011-0003-2.
14. Nozal MJ, Bernal JL, Martin MT, Bernal J, Alvaro A, et al. (2008) Trace
analysis of fumagillin in honey by liquid chromatography-diode
array-electrospray ionization mass spectrometry. Journal of Chromatography A
1190: 224-231. doi: 10.1016/j.chroma.2008.03.019.
What the study does not echo is the common experience of beekeepers, where
Nosema apis was easy to control with Fumagillin, while Nosema ceranae is
much more difficult to control with Fumagillin, even with repeated
treatments.
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