Peter, 

The papers you've been citing keep drawing me back to your first post that contained the survey findings of high DWV levels and relatively low mite counts, and I'm thinking those results may be revealing something we were quick to dismiss with the ensuing discussion and the assumption that those virus levels were vectored by mites- is it possible that they weren't?  If they were, it seems there're a few studies indicating that mite-vectored strains are more likely to produce deformed wings that should have been visible during the season. 

Since the growth of covert DWV can be independent of the vectored stains, my take away from the reading is that a population of covert DWV can grow in a colony even when the mite counts are kept under threshold levels. Add to that the findings of the Benaets paper and over time it seems reasonable that we can expect to experience asymptomatic colony deaths under conditions that converge to cause them.

Should we be considering, as the science suggests, the possibility that the slightly more virulent strains of DWV have replaced earlier strains and as those populations fill in, we may have more unexplainable losses going forward? 

As a practical beekeeping issue, is it possible that we may be seeing the emergence of the need to separate our thinking about some strains of DWV from the varroa/viral complex and consider their impact independently? 


Gisder, S., Aumeier, P., & Genersch, E. (2009). Deformed wing virus: replication and viral load in mites (Varroa destructor). Journal of General Virology, 90(2), 463-467.

http://tinyurl.com/zsy824q








 


  

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