This is a follow-up to my note on potential links between resistance of honey b
ee colonies to ill effects of Varroa vs. presence/absence of viruses vectored b
y the mites. A precedent for Varroa being a vector of harmful bee viruses is wo
rk done by B.Ball, F.M.Allen & co-workers at the Rothamsted Experiment Station,
 Harpenden, UK, who studied the acute paralysis virus (APV) in European colonis
. A few refs.: Ball, 1988, in "Africanized Honey Bees and Bee Mites", edited by
 Needham et al., p. 457; Ball & Allen, 1988, Ann.appl.Biol.113:237; Allen et al
., 1986, J.Apicult.Res.25:100. Now they have shown that Varroa is the vector of
 the deformed wing virus (DWV) which causes adult and brood mortality in heavil
y infested colonies and produces bee sympton previously attributed solely to th
e mites (Abstract in Proc.Annual Meeting of Soc.Invertebrate Pathology, 1992).
The implications of this regarding so-called resistance of African honey bee co
lonies to Varroa was apparently discussed at the meeting. This is still specula
tive but it makes sense - mite resistance may be a function of virus vectoring.