I don't think bleach is safe on carpet in the consentration needed to kill parvo which is about 1/2 to a gallon of water. I personally would never use bbleach on carpet. Bleach is best for hard surfaces, there are some disinfactants that are said to be safe on pourous objects and will kill parvo. KennelSol is said to kill the Parvovirus, you might want to see if can be used safely on carpet, I know there are some products, I can't remember the names. Don't just use any disinfectant, it has to say it will kill Parvovirus. Here's a link for more information.
Cleaning and Disinfecting