CANINE PARVOVIRUS canine parvovirusis one of the diseases vaccinatedfor in the 5 in 1 vaccine Parvo isaninfectious DNA virus that commonly causes severe illness in young and unvaccinated dogs. It is spread by contact with contaminatedfeces, but you don't have to see solidfecesfor the virus to be present Clinical signs include Lethargy as the first sign, and they may not want to eat. They will also often have a fever. As the virus progresses, your dog will begin to suffer from severe vomiting and diarrhea.Severely sick puppies may collapse and have a high heart rate and hypothermiadue to the degree of dehydrationand infection.It primarilyaffects the rapidly dividing cells of the body, meaning that the intestinaltract and bone marrow are the worst affected.