Bill said:
Se we know the mechanism, we know Varroa is a vector for the problem,
we know that nosema can also be implicated, but not as strongly as
virus, and on.
I'd argue that this is not necessarily true. We don't know what causes
CCD, so we can't know the mechanism - yet.
'Varroa is a vector for the problem' - it appears to be a vector of
viruses - it has been shown that at least one virus (VDV-1) can replicate in
varroa mites; although whether its a true vector or simply predisposes bees to
viral attack due to injury seems a bit unclear.
But varroa has not been shown to be the vector causing CCD, since many CCD
operations did not have a varroa problem. Some did, and some had a major
varroa problem, but not all. Several have tried to blame varroa but have
had to admit it wasn't a marker when they looked at their own data.
'Nosema can also be implicated' - I agree, and the Higes group thinks
Nosema is the cause, but some other investigators on both sides of the pond
don't agree.
'Nosema ... but not as strongly as virus' - I haven't seen that data.
Higes and associates certainly would not agree.
Lots of speculation about viruses, IAPV is the only one so far that has
been called a marker, but that argument seems to be losing ground. New work
pointing to picorna viruses interesting, but remember, most bee viruses are
small, picorna-like viruses. So in essence, this is back to just blaming
bee viruses in general.
Bottom line, there still is no known cause of CCD. Whether CCD is new?
I've never said it was new. I think we've seen it before. Whether it dates
back to the 1800s, I don't know. However, I think what Bill Wilson first
called Disappearing Disease, that he suggested was a genetic defect
traceable back to two U.S. bee labs and spreading through the queen breeders of LA
and TX, then followed in the mid-1970s by appearance in 27 states - that
sure sounds like CCD.
Only missing symptom, the lack of robbing - but did anyone look for this at
that time? If Dave Westervelt and I hadn't mentioned it, you'd not be
reading about it now. After we saw it, we had beekeepers saying - I saw
it, but thought it was something unique to my bees, or thought it was a
result of something I was doing.
CCD may be like human flu, the pathogen - and my best guess is that it is
pathogenic- may change, mutate, or express itself under specific
environmental conditions. If human flu stayed the same, we wouldn't have the
pharmaceutical companies racing to produce a different vaccine every year or two.
We see periodic waves of flu in humans, sometimes mild, sometimes more
severe, with some worried about the next pandemic. No reason to expect
something similar may not happen with bees.
Jerry
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