> Are Nosema spores in honey still viable?
> Have any studies looked into honey being an infection vector?
Yes, and yes.
But temperature alone (hot or cold) seems a good way to kill most of the
spores.
Honey stores can easily reach temps like 33 C (91 F) and -20 C (-4 F).
The high or low temps need to be maintained for some number of days to
render the nosema ineffective.
I caught quite a bit of heckling here on Bee-L in the mid-2000s for saying
this same thing - that nosema C stayed viable on comb, but Nosema certainly
did "infect comb", and clearly could be transmitted by "infected" comb.
(Several USDA employees were canvassed, and none of them were they willing
to speculate for the person asking them, as they did not want to me
misquoted about something they had not actually tested, but I was already
doing acetic acid fumigation, and using zinc-oxide hearing-aid batteries as
"lack of oxygen detectors", as the batteries stop making voltage when the
oxygen level drops, which is a handy way to measure your fume concentration.
But heating supers in a hot room or a stack is much easier than
pallet-wrapping stacks of supers and fumigating them.)
> Consuming 50lbs of Nosema infected honey
> over a winter would likely potentially (theory)
> be one of the reasons why spring Nosema is
> worse in cold climate colonies
Yes, this is possible, moreso in mild climates, or for hives that are stored
indoors, and thereby kept out of the very cold snaps. Note that in Fig 3 in
the paper below, -12 C (+10 F) temps reduced the spore viability to 10%, but
the 10% of spores that survived -12C seemed stay viable indefinitely at that
temp. About 10% of spores seem "cold hardy".
See https://doi.org/10.1093/jee/toaa170
" Nosema ceranae (Microspora: Nosematidae): A Sweet Surprise? Investigating
the Viability and Infectivity of N. ceranae Spores Maintained in Honey and
on Beeswax"
JEE Oct 2020
Free full text is available, but in web, and pdf form.
As an aside, people complain about the Fahrenheit scale as non-metric, but
it is clearly the most useful scale for humans.
At zero F, you need a hat, coat, gloves, and silk long underwear from LL
Bean. At 100 F, you want shorts and a tee shirt. And you have 100 units
between to work out all the wardrobe changes in between.
At zero C, maybe you need a coat, but perhaps not gloves. At 100 C, you and
everyone you love are dead.
At zero Kelvin everything's dead. At 100 Kelvin, everything's still dead.
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