There is a virus, Fiv (feline immunodeficiency virus), which has a distant genetic relationship with HIV, the AIDS virus. Both affect the immune system and for both there is no preventive treatment or vaccination. But it is improper to talk about feline AIDS. The Fiv, in fact, is not transmitted by sexual means, as happens with AIDS, but with the bite and therefore with the contact with the saliva. Furthermore, FIV does not affect humans or other animals other than felines. The most common symptoms are chronic infections, stomatitis, gingivitis, in general pathologies affecting the mouth and skin. The disease has a rather slow course and from the moment of infection the animal survives on average from four to five years. Through the serological investigation it is possible to verify the presence of the virus. For the treatment one could use the drugs used against AIDS but, given the prohibitive costs, no one administers them.