Leviticus 22:4-5

4“ ‘If a descendant of Aaron has a defiling skin disease or a bodily discharge, he may not eat the sacred offerings until he is cleansed. He will also be unclean if he touches something defiled by a corpse or by anyone who has an emission of semen,

5or if he touches any crawling thing that makes him unclean, or any person who makes him unclean, whatever the uncleanness may be.