Cats - FIV (Feline Immunodeficiency Virus)

FIV positive cats can live long, happy lives with FIV negative cats and will not transmit the disease as long as there is not a strong biting behavior among the cats. FIV is transmitted through deep bite wounds between fighting cats. FIV positive cats do have a compromised immune system so it is important to keep stress levels low. Best Practices include: neuter/spaying, avoiding stress, give them probiotics, immune supplements like Lysine and provide a good quality diet along with regular vet checkups.

https://www.alleycat.org/resources/feline-immunodeficiency-virus-fiv/

Cornell University College of Veterinary Medicine article