It causes dogs and puppies to not be able to absorb nutrients or liquids. Puppies are especially prone to it because they have an immature immune system. When dogs and puppies contract parvo, they often have diarrhea, vomiting and lethargy. Usually they stop eating and develop a bloody, foul-smelling, liquid stool. Symptoms usually begin with a high fever, lethargy, depression, and loss of appetite.
Secondary symptoms appear as severe gastrointestinal distress, such as vomiting and bloody diarrhea.
In many cases, dehydration, shock, and death follow. Parvovirus is characterized by severe, bloody diarrhea and vomiting, high fever and lethargy. The diarrhea is particularly foul smelling and is sometimes yellow in color. Parvo can also attack a dog's heart causing congestive heart failure. This complication can occur months or years after an apparent recovery from the intestinal form of the disease.