Parvo can be brought home to your dog on shoes, hands and even car tires. It can live for many months outside the animal. Any areas that are thought to be contaminated with parvo should be thoroughly washed with chlorine bleach diluted 1 ounce per quart of water. Dogs and puppies can contract parvo even if they never leave their yards. Parvo virus, despite what you might hear, is NOT an airborne virus.
Some people speculate that birds invading a dog's food dish can deposit the parvovirus there.
If you think you may have come in contact with parvovirus, a strong solution of bleach and water does kill the virus, so you can wash your shoes and clothes, even your hands with it, to reduce the risk of infecting your dog. Rest assured that parvovirus is specific to dogs alone and cannot be transmitted to humans or other pets of a different species, such as cats. Without intense treatment, the victims of parvo die of dehydration. Treatment generally consists of IV or sub-cutaneous fluids and antibiotics. There is no cure.