peter borst wrote:
>No. The explanation of this is that nosema is further advanced in the healthy colonies because they live longer, giving nosema a longer time to develop.

I can buy that...but I don't see it anywhere in the study we are discussing.  In fact, the study states in several places that decreasing levels of nosema ceranae can be a predictive indicator of colony collapse....which is quite another thing all together!

>I think they are elucidating the concept that high levels of particular microorganisms should not be taken as an indicator of declining health and could be the exact opposite.

...I think they are saying quite a bit more than that....that INCREASING levels of noseam ceranae indicate a better chance for survival.

>Healthy colonies tolerate these levels better than colonies that are weakened by some other factor.

...but their data indicates that an increasing infection indicates health (or at least survival) and a declining infection indicates a lack of health...or a lack of survival.

Peter, your reading and mine are very different....perhaps if you did actually summarize the paper for us (as you asked me to do for some reason) you would have seen the following:

1.  In the abstract, nosema ceranae:
"The data show that DWV, Nosema ceranae, Varroa destructor and Vitellogenin can be predictive markers for winter colony losses, but their predictive power strongly depends on the season."

[Here, nosema ceranae is identified as a useful indicator of survival]

2. "Although all colonies were positive for N. ceranae, N. apis could not be detected. The prevalence of N. ceranae was equivalent between the groups in all seasons and ranged between 18.75% and 50% (Table 1). No distinction could be made in terms of numbers of the detected investigated pathogens between the SC and DC groups in any season as shown in table 1"

3.  "N. ceranae quantification showed equivalent titers between summer and fall (P = 0.479)"

4.  "In the surviving group, significant variations were observed between fall and winter: N. ceranae levels decreased (P<0.001)"

[I'll note here that looking for decreasing noseam ceranae levels between fall and winter _might_ indicate survival based on this data, I don't think it's a very useful time of year to discover this...fall is too late to do anything useful to save a colony....it might tell you what colonies to bring to the almonds at best]

5.  "In fall, colonies that collapsed during winter displayed lower levels of N. ceranae than surviving ones (P<0.05).while in the summer N. ceranae levels were similar in both DC and SC groups "

[Again, no difference seen in summer...but the surviving colonies HAD A HIGHER LEVEL OF NOSEMA CERANAE....if, as stated in the abstract that noseam ceranae is a useful indicator, it seems that it is opposite of what we would expect....the survivors had a higher level of nosema ceranae than those that perished]

7.  "Using a linear model (see M&M) the results show that over all seasons, DWV (P<0.05), V. destructor (P<0.001), N. ceranae (P<0.001) and vitellogenin (P<0.001) could be considered as predictive markers for winter losses."

[Am I wrong by concluding that nosema ceranae predictivie marker for winter loss is a lower (or decreasing) level...seems that way to me from the rest of teh study]

8.  "Then in summer only V. destructor (P<0.01) could be considered as a significant predictive marker while in fall, DWV (increased; P<0.01), V. destructor (increased; P<0.01), N. ceranae (decreased; P<0.05) and Vitellogenin (decreased; P<0.05) could be considered as significant predictors of colony collapse."

[They are saying clearly here that identifiying decreasing levels of nosema ceranae predicts collony collapse].

9. "Our results support that N. ceranae is not involved in colony collapse, because no significant differences were observed between colonies that died during winter and those which survived.  Likewise, we did not observe an increase of N. ceranae titers from summer to fall, even in December when colonies were about to die."

[This seems to contradict what is stated elseshwere...that nosema ceranae is a useful indicator of what colonies will collapse over winter]

deknow

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