FAIL. My wife has been trying this on me for years with no ill effect.
Yes, but the likelihood of getting an infection from a single virus is very low. HIV is actually fairly incompetent at getting into the body and infecting cells. It requires a significant dose of viruses to have a good chance of getting an infection. Once it has a foothold in your body, you’re very likely to die from it, at least without aggressive drug treatment.
Well, if we’re talking infectious agents, the LD50 for Anthrax is around 10,000 spores, and each spore weighs 1 trillionth of a gram, so a lethal dose would be around 10 nano grams.
Information here.