https://www.npr.org/sections/thesalt/2019/06/19/733761393/more-bad-buzz-for-bees-record-numbers-of-honey-bee-colonies-died-last-winter
Interestingly, they cite the new research which indicates Varroa feeds on "fat body" tissue not hemolymph as previously thought.
https://www.pnas.org/content/pnas/116/5/1792.full.pdf