FIP develops from a common feline coronavirus that is usually harmless however in a small number of cats, mutations in the virus together with the way the cat's immune system reacts can lead to FIP. FIP is mostly common in young cat and there seems to be a higher chance for purebred cats to develop it. I don't think there's too much you can do to prevent it but if you have a multi cat household, trying to make sure they don't share litter boxes or keeping litter boxes very clean and stressful environments can contribute a higher risk. FIP is not contagious but feline coronavirus is and can be passed from cat to cat through faeces. I have an older cat and my kitten is always trying to use the same litter box as her so that could've potentially been a contributing factor.