Mishnà su Levitico 14:8

He who touches a dead sheretz, or semen, or he that has suffered corpse uncleanness, or a metzora during his days of counting, or hatat waters of insufficient quantity with which to perform the sprinkling, or carrion, or an object ridden upon [by a zav], defiles at one [remove] and disqualifies [terumah] at one [more remove]. This is the general principle: anyone who touches anything that according to the Torah is a "father of uncleanness" defiles at one [remove] and disqualifies [terumah] at one [more remove], except [for the corpse] of a human. If he had become separated, he defiles at one [remove] and renders [terumah] unfit at one [more remove].

If it broke out covering all of his skin all at once: If this originated in a condition of cleanness, he is unclean; But if it originated in a condition of uncleanness, he is clean. One who becomes clean after having been isolated is exempt from the uncovering his head and rending his clothes, from shaving his hair and from bringing the birds. If he becomes clean after he had been certified unclean, he is liable to all these. Both convey uncleanness by entering.