Leviticus 22:4-5

4Whatsoever man of the seed of Aaron is a leper, or hath a flux, he shall not eat of the holy things, until he is clean. And he that toucheth any one that is unclean by a dead person, or a man whose seed of copulation hath passed from him;

5or a man that toucheth any crawling thing whereby he becometh unclean, or a man by whom he may become unclean, whatever may be his uncleanness,