Ah, I see. I need to read up more on feline coronaviruses, but my understanding is that the disease itself (FIP) is not transmissible per se. One cat with FIP won't give FIP to another cat, for example - it's a syndrome that is as much cat-dependent as it is virus dependent.

The coronaviruses themselves (there are various strains) are transmissible, but you need a specific mutation in a chronically infected cat to cause FIP. Once that virus has mutated, it may infect other cats, but won't cause FIP. I am not aware of any particular strain that is guaranteed to mutate and produce FIP in every (or even most) cats.

Does that make sense?