My puppy has been exposed to parvo for about 4 weeks ago and is showing no sign of parvo is she ok??

If your puppy was vaccinated within a week after coming in contact with the parvo virus you should be fine. If your puppy has never been vaccinated you might want to take precautions because a virus can live inside its host for years with out showing any signs. Stress, loneliness and other things can make the virus visible. not trying to frighten you just telling you some things i have found out from my vet when my dog had caught the distemper virus