The main sign of Coronavirus in puppies is watery diarrhea. It differs from the diarrhea produced from eating trash in not containing much mucous. It differs from the diarrhea produced by Parvovirus in that it rarely contains digested blood. Some pups with the disease vomit, but others do not.
Coronavirus diarrhea is often less violent than Parvovirus diarrhea. However, there is enough overlap of symptoms so that Coronavirus can not be differentiated from Parvovirus by clinical signs alone.
Coronavirus diarrhea typically lasts 2-4 days and very few puppies die from it. If puppies do die, there are usually other problems occurring at the same time, such as parasites, dual infection with Parvovirus, or malnutrition.
Bloated & Tight Abdomens
Puppies they are often bloated or tight and have enlarged mesenteric lymph nodes in their abdomens.
How The Disease Progresses
Virus Attacks Small Intestine
Within 2 - 3 days of ingesting the virus, Coronavirus can be found in the upper part of the pet's small intestine. In very rare cases, the virus may also invade the spleen, liver and brain, and lungs.
Fevers & Loss of Body Heat
Puppies with Coronavirus rarely have a fever. This is true of many infections in puppies because they lose body heat so rapidly.
Onset of Diarrhea
During this same period diarrhea begins. Diarrhea usually lasts 2-7 days. The diarrhea is due to malabsorption of nutrients and a deficiency in digestive enzymes.
Most infected dogs shed Coronavirus in their stools for 6-9 days. But shedding can be prolonged in some pups. Most puppies recover after a few days of diarrhea and poor appetite. However, puppies less than 3 months of age may die of the virus if they are weakened in some other way. This could be due to a 2nd disease, being the runts of the litter, or being the pup of an over-bred, poorly maintained mother.