Parvo is a virus that affects rapidly dividing cells and destroys the crypt cells of the villous epithelium of the small intestine. This causes vomiting, hemorrhagic diarrhea (bloody diarrhea), lethargy, and shock. All puppies that are not properly vaccinated and dogs with compromised immune systems are at risk. It can live in the environment for months or even years and is extremely resistant to environmental factors and disinfectants. Incubation period for parvo is generally 3-14 days. Once the symptoms occur it is extremely important to have your dog seen as soon as possible as things can progress quickly. Vomiting and diarrhea will result in hypoglycemia (decreased sugar level), potassium, and dehydration. Hospitalization with IV Fluids and supportive care is extremely important to try to keep up with hydration loss.
By getting your dogs on a proper vaccine schedule you can greatly reduce the risk of contracting this nasty virus.