This is not too young. Signs of parvo in puppies include lack of appetite, diarrhoea, vomiting, fever and lethargy. The diarrhoea may be yellow and progresses to a foul smelling bloody liquid stool. Any diarrhoea in puppies is dangerous as they have very little reserve and quickly succumb to dehydration and lack of nutrients. If you suspect parvo, you need to seek veterinary attention for your pup as soon as possible. Parvo strikes fast and survival rates without treatment are low.