I have two cats at home, a boy and a girl, and the boy- Marcus- is a rescue baby.

He got sick a little after Christmas, and we decided to take him in to the vet as he didn't show any signs of getting better.

After blood test and xrays the vet said he's pretty sure Marcus has FIP (though not %100 because there's no specific way to diagnose it)

Marcus is not suffering at the moment, and he's home in hopes that it's not FIP and he'll get better. If he gets worse though it's time to say goodbye..

My question though; my other cat is 6 years old and is there any possible way she can get FIP from Marcus?

I've read that it's both contagious and not contagious, our vet said it wasn't but to keep them away from each other?

They share litter boxes (there's 2) but they are cleaned almost immediately after one of them uses it (give or take a couple hours if we see it right away or not)

Mizzie is showing no signs of being sick, so I hope that that's a good thing since Marcus has been sick about 2 weeks now give or take.

I can't even think of having to get rid of Marcus, let alone both of my babies, and I would feel much better if someone could verify if Mizzie can get sick from Marcus or not.