Parvovirus in dogs is a potentially fatal infection that damages the intestines and causes severe diarrhea and dehydration. With severe dehydration, blood no longer circulates as it should and your dog may die before diarrhea develops. When the intestine is damaged, blood vessels that nourish the intestine are also damaged. The blood vessels break and blood enters the intestine. At the same time, bacteria travel from the intestines out into the blood vessels and are carried throughout the body. Just as diarrhea can cause death, an infection in the blood (septicemia) can also cause death.
Dogs develop parvovirus infections. Some breeds (Rottweilers, Doberman Pinschers, English Springer Spaniels) appear more susceptible than others to parvo, but any stressed dog is susceptible. Dogs stressed by kenneling, being in an animal shelter, or being weaned and placed in a pet store are at risk.
Poor sanitation and crowding increase the likelihood your dog can become infected with parvo. Puppies are more susceptible than adult dogs.