I’m not really sure how I can answer your main question, sorry, but maube you should throw away your trash in a dumpster trash can.
http://farm8.static.flickr.com/7066/6989833803_78c05b1ed4_m.jpg
I throw away my trash in these, and even I have trouble reaching inside.
i believe the virus is active in the environment for 3-7 weeks. i’d get him checked out before you bring home another cat, and discuss prevention with your vet.