A paper looks deeper at the variants of DWV. It isolates a distinct (Type C) quasi species from hives in Devon, UK and on Kauai (non-Varroa Hawaii). It estimates the age from branching off the master Type A at 319 years. It notes introgression forming new combinations (Type A-C) in the Devon population.
It notes that non-Varroa transmitted DWV may absorb hyper-virulence from the DWV Type A strain. It speculates that colony losses in treated colonies may result from these new non-Varroa hypervirulent combinations.
http://www.nature.com/ismej/journal/vaop/ncurrent/pdf/ismej2015178a.pdf
It notes that non-Varroa transmitted DWV may absorb hyper-virulence from the DWV Type A strain. It speculates that colony losses in treated colonies may result from these new non-Varroa hypervirulent combinations.
http://www.nature.com/ismej/journal/vaop/ncurrent/pdf/ismej2015178a.pdf