Understanding canine parvovirus infection

By Dr. Elizabeth Knabe, DVM

Wildwood Animal Hospital and Clinic LLC

Canine parvovirus (CPV), also known simply as parvo, is one of the most common viruses causing diarrhea in puppies younger than 6 months old. It is related to viruses of the feline family and somehow transferred to the canine species over a 10-year period beginning in the late 1970s.

In the ‘70s and early ‘80s, there were quite a number of cases of CPV as it was highly contagious and dogs had no immunity to it. There was no vaccine for it, though effective vaccines would soon be produced.

Unfortunately, the virus sometimes proved fatal in the population of young dogs that often had co-infections with other viruses and intestinal parasites. Co-infections weakened their systems and made the CPV infections worse.

CPV mainly affects puppies, but dogs of any age can be affected — as can any breed. The younger puppies tend to be more severely affected by it. CPV is caught via the oral route from contact with infected feces. The virus is very stable in the environment and is resistant to freezing temperatures and many common disinfectants. Dogs that have recovered from it can shed virus in their feces for weeks. Cases of CPV occur in shelters and pounds where high numbers of dogs are housed. Unvaccinated dogs are also at risk.

With CPV infection the dog will develop signs after an incubation period of seven to 14 days. Owners will report seeing profuse, watery diarrhea; vomiting; lack of energy; loss of appetite; and often rapid, severe weight loss. There could be other reasons for these signs, but CPV will be at the top of the list of possibilities.

CPV affects multiple body systems, but the effects on the intestines are the most dramatic. Viruses attack and destroy tissues lining the intestines so that body fluids leak into the gut and nutrients cannot be absorbed. Dogs develop severe dehydration due to the fluid losses from diarrhea and vomiting.

Treatment usually involves hospitalization for intensive fluid therapy and antibiotics to stop bacteria from the intestinal tract from causing widespread infection. The pet will need to be isolated from other dogs in a special ward. Staff will wear protective gowns and gloves to avoid accidentally carrying the virus back to other dogs or their own pets at home. Care is very labor-intensive, and veterinary technicians will spend a lot of time caring for the dog’s physical and emotional needs until recovery.

The good news is that there are very effective vaccines, and the disease incidence has dramatically reduced because of them. Puppies will need a series of vaccine boosters to establish immunity, and adult dogs will require regular boosters for life.

Wildwood Animal Hospital and Clinic LLC is located at 210 Airpark Road in Marshfield and online at wildwoodanimalhospital.net.