In all the years I have been rescuing, I have run across this disease one time. A big old black tomcat showed up at midnight only. He looked very sick, but it was quite awhile before I could successfully trap Captain Midnight. When I did, I rushed him to the vet, had him tested and he was very ill with the disease. I opted to put him down because he was so ill, he was old, and he was feral. I came home and bleached everything he touched and waited anxiously to see if any of my other cats would get sick, (none did)
Cats can carry this disease, and not be sick, but be a carrier that will get others sick. They can live with this disease, and they are living longer these days thanks to new food products on the market and better health awareness. You would have to make this decision of what to do based on what your vet tells you, and about the cat itself. There is a website where you can put these cats up for adoption, but you would have to socialize the cat first.