We don't test TRN cats either, unless they will be adopted through us. Our feeling is that FIV+ and FeLV+ cats have already exposed the colony, and we are doing the best thing we can--neutering them--to keep the spread of the disease in check.
We don't consider FIV much of a disease in a spayed/neutered group of cats. We allow our FIV+ cats to mingle with our FIV- cats unless someone is a fighter. FIV is only passed through sex, from which everyone is retired, and a DEEP bite penetrating a mucous membrane, 99.99% of the time associated with fighting over sex and territory, which spayed/neutered cats don't do. We have never had any transmission of FIV.
Not so with FeLV! If we take in an FeLV+ cat, we keep him/her separate until we get the cat adopted. However, in a community cat colony, again, we don't test unless the cat is ill, and we are doing the best thing we can--spay/neuter--to stop the spread of both diseases.
#CommunityCatManagement