Having unprotected relations with a squirrel who is infected with squirrel aids will result in squirrel aids, or alternatively, having unprotected relations with a person/animal/fury who have acquired squirrel aids from an infected squirrel.
Symptoms: headache, nausea, diarrhea, the overwhelming desire to have nuts on your chin.
However this will cure most nut allergies.
Man 1: Hey did you hear that Roy was having unprotected relations with a squirrel?
Man 2: Do you mean sex?
Man 1: Why yes, I do.
Man 2: Oh no! Has he acquired the dread squirrel aids?"
Man 1: Yes he has. It has progressed so far that he has nuts on his chin right now.
Man 2: What a tragedy.
Man 1: Indeed.