can't speak for hip, but believe they take viruses into consideration via
selection of only "healthy thriving survivors" without tratment for two
years...as regards variability
in virulence with differing mite strains being involved, don' think
anyone has gone
beyond anecdotal evidence yet of such a correlation, at least to my
knowledge, and
it should surely be looked at for co-evolutionary host/parasite
implications...as per
biological controls for varroa, preliminary results with a mite
parasitic/pathogenic fungus (hirsutella thompsonii) in florida are
promising, and certainly deserve further
study along the same lines as bacillus thuringiensis for control of wax
moth and
possible hymenopteran parasitoids (parasitic wasps) and nematodes as well
on the small hive beetle...personally, swarms/feral hives still hold out
the slim lottery-like possibility of finding survival/tolerance
mechanisms by natural selection, enough so to keep on collecting and
observing them over time.