I cannot give you a definitive answer, but I can share my experience. I lived in a big city for a time and rented 2 different apartments. They asked specifically if you would have a cat on the rental application. There was a large surcharge if you said yes, because health regulations required them to take up the carpet before you moved in, put a sealant on the flooring, replace the carpet, and finally put completely new carpeting on the floor when you moved out. From this experience, I would hazard a guess that there is something sinister about cat urine and feces.