Dogs may have the following symptoms in the early stages of parvovirus infection:

Vomiting: Frequent vomiting is one of the common symptoms , which may include undigested food or yellow bile.

Diarrhea: Loose or watery stools that may contain blood or mucus.

Loss of appetite: The dog may lose interest in food and be unwilling to eat.

Low energy: May appear tired, listless, or less active.

Fever: Body temperature may rise and feel warm when touched.

Dehydration: Due to vomiting and diarrhea, dogs may show signs of dehydration, such as dry mouth and reduced skin elasticity.