טמא טמא

There are three types of טומאה that involves quarantine. There is the טומאה of coming in contact with the dead, called טמא מת. One who has this level, must stay out of one of the camps of Israel.

The second type is טומאת זב, that is equivalent to gonorrhea in men, and an extended flow of blood for a woman. For this טומאה, they needed to be outside two camps.

The third type is צרעת, or leprosy, and the quarantine is outside all three camps. This is considered most severe because it is connected with לשון הרע.

There were actually three different boundaries in Jerusalem when the Temple stood, that is equivalent to these three boundaries. Two were in the Temple, and the third, Jerusalem inside its walls.

The Torah tells us that the leper would warn anyone coming close to him, by shouting, טמא טמא. The first time he announced he was טמא so that nobody would touch him. And the second טמא was to ask people to pray for his recovery.

The Gemara says that this is the source for putting tomb stones on graves. They serve as a warning to others, to be careful not to get defiled.