I think you can sanitize it, Lindsay. Scrub with soap and a little bleach - I use Clorox Clean-up bathroom cleaner. Then set it out where it will bake in the sun. Sunlight is death to fungus, generally. Don't use it again until it is thoroughly dry and baked - at least a week of sunshine, I'd think.
I"m betting you'll save that plant, just keep it dry for at least a few days. Mist the leaves only. Keep it away from the others for a few weeks until you're absolutely sure the plague is gone.
Let us know how it goes, ok? Have you done an inventory on the rest of your Catt herd? As you said, this may have only been a test run.
