Lev. 14:33 concerns leprosy in a house. This seems strange, but they had a good reason for relating the infection in a building to the infection in a person. Both conditions were caused by microorganisms, which were unknown until the invention of the microscope late in the seventeenth century made it possible to see the bacteria and molds. The Hebrew word Tsara-at did not mean disease to those who called that condition Tsara-at. A better translation might be Plague, because in the house this is a reference to mold, which can be a very serious problem for any building even today, so we can relate to the drastic measures of Lev. 14:33-48. It was not until the seventeenth century that man discovered microorganisms, so now we know that there are different causes of those conditions, but several thousand years ago they were simply recognized as plagues.