Pet Boarding & Daycare

What Every Pet Business Needs To Know About Parvo

What Every Pet Business Needs To Know About Parvo

By Dr. Melissa Bourgeois

Canine parvovirus (CPV) is a non–enveloped, single-stranded DNA virus that replicates in rapidly dividing cells.(1) The CPV–2b strain has been considered the most prevalent form of canine parvovirus worldwide, however, a new strain, CPV–2c is also found in the US and is increasing in prevalence.(1)

Canine parvovirus is transmitted through the oral–fecal route and is highly contagious. One single gram of feces can contain up to 10 million infective doses of parvovirus.(1) Canine parvovirus is shed extensively in the feces for up to 10 days post–infection as detected by fecal ELISA methods, but can be detected in the feces for several weeks with polymerase chain reaction (PCR) assays.(2)

Unvaccinated dogs of any age and breed are at most risk for parvo infection. However, the majority of parvo cases are seen in puppies from 6 to 20 weeks of age, and most often before the puppy can complete a vaccination series. 

Once ingested, the virus replicates, and then relocates to the rapidly dividing cells of the bone marrow and gastrointestinal crypt epithelium within 4 to 5 days of exposure.(1) Viral replication in the dog’s body results in damage to the intestines which results in typical signs of parvo including vomiting, abdominal pain, and bloody diarrhea.(1) Bacteria leaked into systemic circulation from this damage, combined with a lack of production of protective white blood cells from the infected bone marrow, leads to sepsis.(1)   

The virus can remain in the environment for up to one year. Prevention of exposure to parvo is extremely important but can be challenging since environmental contamination can be extremely high.  Any potential infected area should be cleaned first with soapy water to remove debris and then disinfected with 1 part sodium hypochlorite (bleach) solution to 32 parts water.(1)

The American Animal Hospital Association (AAHA) Vaccination guidelines recommend that puppies receive parvo vaccinations every 3—4 weeks between 6 to 16 weeks of age.(3)  Repeat vaccination should occur at 1 year, then at 3–year intervals.(3) Clients should be educated about the risk of parvo, especially when dealing with a local parvo outbreak. 

Pet owners should be encouraged to restrict puppy access to dog friendly areas, such as dog parks and doggie daycares, until their vaccination series are complete. Pet owners should also consider waiting until vaccination series are complete before enrolling their puppies into training classes.

Remember, when you are in a parvo hot zone, any area that a dog has visited should be considered contaminated—and this means your own facility.  Make sure your staff is thoroughly trained in the proper way to clean and disinfect areas of potential contamination such as the lobby, grooming areas, and kennel. Don’t forget that most of your clients’ pets will also spend time outside of your facility.  That area should be considered a contaminated source and should also be cleaned thoroughly and regularly. However, lawns that are contaminated are virtually impossible to clean, therefore unvaccinated dogs should not be allowed in these areas after a sick dog has been on them.

Melissa Bourgeois, DVM, PhD, DACVM (Virology, Immunology) graduated from the University of Florida, College of Veterinary Medicine in 2007 with a DVM, and in 2010 with a PhD in veterinary medicine, focusing on gene expression in the equine host following West Nile virus infection. Dr. Bourgeois became a diplomate of the American College of Veterinary Microbiologists (ACVM) in virology (2011) and immunology (2013). Since July 2015, Dr. Bourgeois has worked for Merck Animal Health as a senior drug safety specialist.

1 Mazzaferro EM:  The Parvo Puppy:  What is the Best Approach and What’s New, International Veterinary Emergency and Critical Care Symposium 2013.

2 Green CE, Decaro N:  Canine Viral Enteritis. Infectious Diseases of the Dog and Cat, 4th Edition, St. Louis, MO, Saunders/Elsevier:  2012:67-75.

3 AAHA Vaccine Guidelines, updated 2011,