This is a dirty word in most veterinary clinics.  We often refer to Spring as “Parvo season”, but only because we seem to have many parvo positive cases this time of year.  There really is no season that is related to weather, it is most likely due to the many litters of puppies being born in the spring of the year.  I want to break this down into a very simple explanation about this horrible disease.  Parvo is a nasty virus that strikes the immune system and intestinal lining.  It presents with vomiting, bloody diarrhea and lethargy (weakness). 

Not all cases come with the same degree of severity.  Some patients have functioning immunity to the virus and mount a hefty response which reduces the severity and duration of the symptoms; however, most of the cases we see are very young puppies that have not been fully vaccinated, and their symptoms can be quite severe.  We also see some older puppies and even adults if they are not properly vaccinated.  There is no specific anti-parvo medication which makes treating this illness so difficult.  We must treat symptomatically and supportively while the virus runs its course.  Treatment usually includes IV fluids, anti-nausea meds, supportive IV nutrition, antibiotics (to prevent secondary bacterial infections), and a lot TLC (cleaning up the endless river of bloody diarrhea and vomiting).  These poor little babies look so pitiful because they feel so bad.  Parvo can hit them very hard and in some cases be fatal even with hospitalization and ‘round the clock care.  

This virus is a canine only disease that is very contagious.  I cannot stress this enough.  Many clients think that if the dog does not go around other dogs they do not need to vaccinate against parvo.  However, I would strongly caution against this mindset.   The outside world is strewn with parvo virus from many sources, but owners also do not comprehend how they can bring it back to their dog.  Many times, we have had dogs become exposed when their owners went to visit a family member whose dog has/had parvo and the virus hitched a ride on their shoes. 

Vaccination is the best way to prevent this disease.  For young puppies, we recommend a series of 3 vaccines (3-4 weeks apart) starting no earlier than 6 weeks of age.  For older puppies, 6 months of age or older, and adults that are not previously vaccinated, 2 vaccines (3-4 weeks apart) are usually enough, but 3 is still better.   Yes, I do recommend a yearly booster of this vaccine, even for adult dogs.  There are some vaccines out there that are labeled as a 3-year vaccination.  The vaccine must be manufactured and labeled as a 3-year vaccine.   I do not recommend vaccinating puppies prior to 6 weeks of age.  The reason for this is that their immune system is questionable as to the ability to respond to the vaccination due to maternal antibodies. 

Treating puppies in hospital for parvo virus is intensive and specialized due to the contagious nature of the virus and the shear quantity of mess that these puppies produce.  We must place them in isolation, a separate room quarantined from the rest of the hospital.  Prior to going in that room, we must don appropriate protective apparel (gowns, booties, gloves) and then decontaminate when leaving.  These babies require a lot of attention and multiple man hours of hands on care, cleaning, and medicating while they are in the hospital.  It often requires two people simultaneously to care for these patients.  As you might assume from this description, caring for these patients is also financially intensive.   We usually estimate treatment to start around $800 (this includes the initial intake, testing, IV catheter, fluid therapy and care for 3 days).  Duration of treatment can range from 48 hours to 2 weeks.  A very high percentage of our in-hospital patients survive and go on to live normal lives.

Hospital policy regarding parvo is also specific.  If we have a pet that is coming in that meets certain criteria, they must be tested for parvo prior to clearing them to be in the common areas of the clinic.  The test is fairly accurate and fortunately, results are rapid. We will know in 10 minutes if the dog is shedding parvo virus.  Parvo suspects are those patients presenting with any two of the following symptoms (Vomiting, diarrhea, and lethargy) and not current on their parvo vaccinations.  In other words, a 10-week-old puppy with vomiting and lethargy with only 2 parvo vaccinations would qualify.  If the test is positive, they would only be admitted to the isolation ward, not the general areas of the clinic, including the reception area.  This ward has external access to allow for intake and discharge via that exit without having to go through the hospital.  This policy is to protect the health of our patients that are not yet fully vaccinated or are sick and debilitated.   

Once puppies are progressing with no more vomiting and they are holding down food and water consistently over a 48hr period, we can consider sending them home to finish healing.  We consider these patients to be contagious for at least 2 weeks after all clinic signs have resolved.  That includes diarrhea which can last at least 2 weeks beyond the time they are sent home.  During this contagious period, you must keep these puppies isolated.  They may act like they feel great and you may be tempted to take them out to the pet store to get a new toy, but they are still a source of infection to other dogs that are not up to date on their vaccines.  Unfortunately, in a few rare cases, dogs can become chronic shedders of the virus and appear clinically normal but still have detectable virus in their stool for years after infection.  You cannot detect these carriers with visual inspection. 

This disease is very common and very frustrating, to owners and veterinarians alike.  We see multiple cases every year.   I wish for nothing more than to have our isolation ward obsolete, but until that time comes, we will continue to push prevention and treat those that contract this awful disease.