My puppy came down with parvo. Can I use Clorox® on pine wood floors?

Regarding your wood floor, as long as it has a finish (in good condition) on it that effectively makes it a hard non-porous surface, a singular bleach treatment should be OK.  Even so, you should still test a small, less visible section first so you will know what to expect from the treatment.  Our EPA-registered protocol to kill canine parvovirus on hard non-porous surfaces is as follows: prepare a disinfecting solution of ¾ cup Clorox® Regular-Bleach and 1 gallon water.  Pre-wash the areas, then mop or wipe with the disinfecting solution.   Let stand for 10 minutes, then rinse thoroughly and air dry.  Consider working in small sections to be sure you can manage rinsing quickly and efficiently, and be sure the room is well ventilated.  You should also wear eye protection and gloves because you will be working with the bleach solution for a prolonged period of time.