Parvovirus: Fighting a Concealed Killer


Sick puppy - Image courtesy of

Ms. Olsen arrived looking very concerned about her 12-week-old puppy’s vomiting and bloody diarrhea. The front staff immediately isolated them in a designated exam room, fearing a contagious disease. Kono had dull eyes sunken from dehydration while his tail barely wagged. Two days of symptoms had taken their toll.

“I got Kono last week,”  Ms. Olsen said.  She also reported that Kono was not yet vaccinated, and that she had taking him frequently to the local dog park.

A parvovirus infection was my primary concern, given Kono’s age, lack of immunization and visits to the dog park.  Other possible explanations were that Kono had intestinal parasites or that he had eaten something foreign.  No parasites were evident on fecal exam.  And, with no history of getting into the trash or swallowing any of his toys, we postponed intestinal x-rays and instead ran a test on Kono’s feces for parvovirus.  A strong positive result gave us our diagnosis.

Kono was very sick.  We hospitalized him for several days, started IV fluids to manage dehydradation, and gave injections to control nausea and infection.  Blood tests showed a low white blood cell count.  Fighting the parvovirus depleted his body’s supply of white blood cells, and the virus suppressed production of new ones.

Parvovirus typically strikes new puppies and inadequately vaccinated young dogs when they come in contact with the feces of infected dogs.   Parvovirus can survive for a long time anywhere that is not regularly disinfected, so dogs can be exposed to the virus from even what appears to be a perfectly manicured lawn, whether by eating grass or licking paws that have come in contact with viral particles.

The incubation period for parvovirus is about 3 to 7 days, after which symptoms emerge.  The disease disrupts the intestinal lining, causing vomiting and bloody diarrhea, and it suppresses the immune system.  There is no specific medication for parvovirus. Treatment consists of supportive care to counteract the symptoms until the dog’s immune system can recover and fight it off.  With appropriate treatment, the survival rate for parvovirus is quite high, but without it a dog can die from dehydration and sepsis in a matter of days.

IV fluid therapy is critical to counteract the dehydration and electrolyte imbalances caused by vomiting and diarrhea.  Some dogs even require IV nutrients or transfusions.  Antibiotics are given to treat infection caused by intestinal bacteria that travel across the damaged intestinal lining into the bloodstream. Medications to control vomiting are also often necessary.

Fortunately for Kono, after 48 hours of uncertainty, his symptoms subsided. By the fourth day of fluid therapy, anti-nausea drugs, and antibiotics, he happily wiggled during his morning checkup.  Since he had successfully held down water the night before, we offered him a small amount of bland food which he ate it eagerly.

At the end of the sixth day, Ms. Olsen returned to pick up her recovered puppy.  The plan was to keep Kono at home until he had finished his course of puppy vaccines and to diligently clean up after him to minimize fecal contamination of the environment for at least the next several weeks. She was also advised not to allow any unvaccinated puppies into her home or yard for the next year and a half.

I checked Kono one last time to make sure he was ready to go home, and for some last puppy kisses before we sent him on his way.  As I left the isolation ward, it echoed with the yipping of a happy puppy.
Dr. Deirdre Brandes is a veterinarian at the Rancho Santa Fe Veterinary Hospital, now open at the Helen Woodward Animal Center.  She can be reached at, or 858-759-8797.  The cases described in Veterinary Vitals are true stories, but the author has changed details about the patients to protect their privacy.