According to About.com, after exposure to the parvo virus, a puppy typically shows symptoms within five to 11 days. Physical symptoms often begin with vomiting and include high fever and diarrhea.
About.com states that puppies infected with the parvo virus often appear depressed, and they sometimes stop eating and drinking. Occasionally the onset of the disease is sudden and severe, with stomach pain accompanied by depression. In these cases, dogs often go into shock and die suddenly.
The disease is spread through direct contact with infected fecal material. Dogs that lick infected droppings ingest the virus and become ill. About.com indicates that 20 percent of parvo-infected puppies die, even if treated.