Varroa mites are a fact of life with bees now. I've had some colonies that were Africanized that did not have as bad of a problem because Africanized bees are more hygenic. Oh, and their stings are no worse than European bees, they just sting you 20:1 to the Europeans. The LD 50 of a bee sting for a normal (non-allergenic) person is 10 stings, or for a 200lb man, 2000 stings. I'd venture to say that you'd never risk that in European colonies, but Africanized could possibly reach that level of response. Most deaths from Africanized honeybees and their hybrids come from heart-attacks from running from them. Not from a lethal dose of stings.
A trivial tidbit: The body's reaction to a beesting is to produce cortisone at the site of the sting. The same thing that the doctor gives arthritic patients. The old-timers were correct, getting stung in an arthritic joint does produce relief from arthritis.
