Leprosy, also known as Hansen’s disease, still exists today but is treated with antibiotics. There was no effective treatment or cure in the ancient world and the term leprosy was used to describe a variety of different skin diseases and conditions. The key was examination, identification and when necessary, isolation. Preventing the spread of the disease was their best defense for the health of the entire camp.

Leviticus 13

The LORD spoke to Moses and Aaron, saying:

2 “When a man has in the skin of his flesh a rising, a scab, or bright spot, and it is in the skin of his flesh like the plague of leprosy; then he shall be brought to Aaron the priest, or to one of his sons the priests:

3 And the priest shall look at the infection in the skin of the flesh: and when the hair in the disease has turned white, and the infection appears to be deeper than the skin of his flesh, it is a plague of leprosy: and the priest shall examine him and pronounce him unclean.

4 If the bright spot is white in the skin of his flesh, and appears to not be deeper than the skin, and the hair has not turned white; then the priest shall shut up him that has the infection for seven days.

5 The priest shall look on him the seventh day: and if the infection in his sight be at a stay, and has not spread in the skin; then the priest shall shut him up seven more days. 

6 And the priest shall examine him again the seventh day: and, behold, if the infection is somewhat dark, and has not spread in the skin, the priest shall pronounce him clean: it is only a scab: and he shall wash his clothes, and be clean.

7 But if the scab has spread abroad in the skin, after that he has been examined by the priest for his cleansing, he shall be seen by the priest again.

8 And if the priest sees that the scab is spreading in the skin, then the priest shall pronounce him unclean: it is leprosy.

9 When the plague of leprosy is in a man, then he shall be brought to the priest;

10 And the priest shall see him: and if the rising be white in the skin, and the hair has turned white, and there is raw flesh in the swelling;

11 It is an old leprosy in the skin of his flesh, and the priest shall pronounce him unclean, and shall not shut him up: for he is unclean.

12 And if a leprosy breaks out across the skin, and the leprosy covers all the skin of him that has the infection from his head to his foot, everywhere the priest looks;

13 Then the priest shall consider: and if the leprosy has covered his entire body, he shall pronounce him clean: it has all turned white, he is clean.

14 But when raw flesh appears in him, he shall be unclean.

15 When the priest sees the raw flesh, and pronounces him to be unclean: for the raw flesh is unclean: it is leprosy.

16 Or if the raw flesh turns again, and be changed to white, he shall come to the priest;

17 And the priest shall examine him: and, behold, if the plague is turned into white, then the priest shall pronounce him clean that has the plague: he is clean.

18 If there is a boil in one’s flesh, and it has healed,

19 And in the place of the boil there is a white rising, or a bright spot, white, and somewhat reddish, it shall be shown to the priest;

20 When the priest sees it, if it appears lower than the skin, and the hair of it has turned white; the priest shall pronounce him unclean: it is a plague of leprosy broken out of the boil.

21 But if the priest looks at it, and there are no white hairs in it, and if it is not lower than the skin, but is somewhat dark; then the priest shall shut him up seven days:

22 And if it spreads much in the skin, then the priest shall pronounce him unclean: it is an infection.

23 But if the bright spot stays in its place, and does not spread, it is a burning boil; and the priest shall pronounce him clean.

24 Or if there is any flesh in the skin in which there is a hot burning, and the flesh that burns has a white bright spot, somewhat reddish, or white;

25 Then the priest shall look at it: and behold, if the hair in the bright spot has turned white, and it appears deeper than the skin; it is a leprosy broken out of the burning:  the priest shall pronounce him unclean: it is the plague of leprosy.

26 But if the priest look at it, and there is no white hair in the bright spot, and it is no lower than the other skin, but is somewhat dark; then the priest shall shut him up seven days:

27 And the priest shall examine him the seventh day: and if it has spread in the skin, then the priest shall pronounce him unclean: it is the plague of leprosy.

28 And if the bright spot stays in its place, and has not spread in the skin, but it be somewhat dark; it is a rising of the burning, and the priest shall pronounce him clean: for it is an inflammation of the burning.

29 If a man or woman has an infection on the head or the chin; 

30 Then the priest shall examine the infection; if it appears deeper than the skin, and there is a thin yellow  hair in it; then the priest shall pronounce him unclean: it is a dry scall, an infection on the head or chin.

31 And if the priest looks on the infection of the scall, and it does not appear deeper than the skin, and that there is no black hair in it; then the priest shall shut up him that has the infection of the scall seven days:

32 And on the seventh day the priest shall examine the infection: if the scall has not spread, and there is not yellow hair in it, and the scall does not appear deeper than the skin;

33 He shall be shaved, but the scall he shall not shave; and the priest shall shut up him that has the scall seven more days;

34 On the seventh day the priest shall look at the scall;  if it has not spread in the skin, nor appear deeper than the skin; then the priest shall pronounce him clean: and he shall wash his clothes, and be clean.

35 But if the scall spread further in the skin after his cleansing;

36 Then the priest shall examine him: and if the scall be spread in the skin, the priest shall not look for yellow hair; he is unclean.

37 But if the scall appears to be at a stay, and  black hair has grown up in it; the scall is healed, he is clean: and the priest shall pronounce him clean.

38 If a man or a woman have white spots on their skin;

39 Then the priest shall examine them: and if the bright spots in the skin are darkish white; it is a freckled spot growing in the skin; he is clean.

40 And the man whose hair has fallen off his head, he is bald; yet is he clean.

41 And he that has his hair fallen off from the part of his head toward his face, he is forehead bald: yet he is clean.

42 And if there is in the bald head, or bald forehead, a white reddish sore; it is a leprosy sprung up in his bald head, or his bald forehead.

43 Then the priest shall examine him: if the rising of the sore is reddish white in his bald head, or in his bald forehead, as the leprosy appears in the skin of the flesh;

44 He is a leprous man, he is unclean: the priest shall pronounce him utterly unclean; his infection is on his head.

45 The leporus person with the disease shall tear his clothes, and shave his head, and he shall cover his mouth and cry ‘Unclean, unclean.’

46 All the days the plague is in him he shall be defiled; he is unclean. He must live alone in a place outside the camp. 

47 The clothing also that the infection of leprosy is in, whether it be a woolen garment, or a linen garment;

48 Whether it be in the warp, or woof; of linen, or of woolen; whether in leather or a thing made of leather;

49 And if the infection is  greenish or reddish in the garment, or in the skin, either in the warp, or in the woof, or in any thing of leather; it is an infection of leprosy, and shall be shewed to the priest:

50 And the priest shall look at the infection, and shut up what has for seven days:

51 And he shall examine the infection on the seventh day: if it has spread in the fabric, either in the warp, or in the woof, or in the leather, or in any work that is made of leather; the disease is leprosy; it is unclean.

52 Therefore he shall burn that garment, whether warp or woof, in woolen or in linen, or any thing made of leather, in which the disease is: for it is leprosy; it shall be burned in the fire.

53 If the priest looks, and the plague has not spread in the garment, either in the warp, or in the woof, or in any thing made of leather;

54 Then the priest shall command that they wash the thing that is infected, and he shall shut it up seven more days. 

55 And the priest shall examine after that it is washed: and if the infection has not changed color, and has not spread; it is unclean; you shall burn it in the fire; whether the rot is in the front or in the back. 

56 If the priest looks, and the disease be somewhat dark after the washing it; then he shall cut it out of the garment, or out of the skin, or out of the warp, or out of the woof:

57 If it appears still in the garment, either in the warp, or in the woof, or in any thing made of leather; it is spreading: you shall burn that which has the disease with fire.

58 And the garment, either warp, or woof, or whatever thing of leather it is, which you shall wash, if the infection has departed from them, then it shall be washed the second time, and shall be clean.”

59 This is the law of the plague of leprosy in a garment of woolen or linen, either in the warp, or woof, or anything made of leather, to pronounce it clean, or to pronounce it unclean.

See also: Leviticus 13 in ESV, HCSB, NASB and NIV via Bible Gateway.