Leviticus 22:4-5

4“If any of Aaron’s descendants has a skin disease or any kind of discharge that makes him ceremonially unclean, he may not eat from the sacred offerings until he has been pronounced clean. He also becomes unclean by touching a corpse, or by having an emission of semen,

5or by touching a small animal that is unclean, or by touching someone who is ceremonially unclean for any reason.