There is a lot of misinformation on the internet and even in the veterinary community about FIP. No FIP itself is not contagious. This disease is caused by a corona virus. Over 80% of cats have been exposed to this virus. In cats that develop the disease FIP the virus has undergone a mutation within that individual cat. A sibling of a cat that has had FIP is more likely to develop the disease because their genetics are similar making them more likely to have the mutation occur.
Your older cat has already been exposed to the corona virus. It is highly, highly unlikely she will get FIP. Again it is NOT contagious; it results from a virus mutation that occurs in individual cats.
Your older cat has already been exposed to the corona virus. It is highly, highly unlikely she will get FIP. Again it is NOT contagious; it results from a virus mutation that occurs in individual cats.