This person has bugs. It's not the same as telling someone he or she wears too much perfume or has body odor.
Bugs are a whole new ball game.
I assume it is you, and you would rather that it be someone else. If you are worried that this individual has lice, bed bugs or some other transferable creature, you must either distance yourself from that person or confront her or him. There is no delicate way to deal with this kind of hygiene problem. First you have the problem of learning if indeed this individual has bugs. If it were a lice problem of a child in school, you could have the nurse inspect the person.