The canine parvovirus (CPV) infection is a highly contagious viral illness that affects dogs. The virus manifests itself in two different forms. The more common form is the intestinal form, which is characterized by vomiting, diarrhea, weight loss, and lack of appetite (anorexia). The less common form is the cardiac form, which attacks the heart muscles of very young puppies, often leading to death. The majority of cases are seen in puppies that are between six weeks and six months old. The incidence of canine parvovirus infections has been reduced radically by early vaccination in young puppies.