posted: by: SVVC Tags: "Clinic Specials" "News" 


OVERVIEW: Canine Influenza (“Dog Flu”), is a highly contagious respiratory disease caused by two viral strains of Canine Influenza Virus Type A.  

  1. H3N8 (a flu strain previously diagnosed in horses) was first seen in dogs in Florida in 2003.  Since that time, H3N8 has been confirmed in 41 states.  
  2. H3N2 (a flu strain previously seen in birds in Asia) was first seen in dogs in Chicago, IL in 2015.   As of June 2017, this virus had spread to 31 states.  

SPREAD:  Almost all dogs are susceptible to CIV because most have never been exposed before.  All dogs, despite age, sex and breed can be at risk.  Neither strain has been shown to infect humans, however, in rare cases it has been suspected that this virus can spread to cats.  Infected dogs will actively shed the virus in upper respiratory secretions for up to 24 days (this is the recommended isolation period).  

The Canine Influenza virus can spread through:

  1. Direct Contact (nose to nose, or dog kisses)
  2. Aerosolization (particles in the air from coughing, sneezing, barking or breathing)
  3. Human Contamination (clothing, shoes, hands or toys that have touched an infected dog)   

SYMPTOMS: If a dog gets infected with Dog Flu, signs will likely develop within 1-4 days.  

  • 20% of infected Dogswill not show symptoms (you may not recognize them in public)
  • 50-70% of infected Dogsdevelop symptoms mentioned above and should remain isolated
  • 8-10% of infected Dogsdevelop pneumonia and dehydration (can require hospitalization)

Symptoms can last from 14-60 days depending on the severity of the infection.  The signs of Dog Flu are often indistinguishable from “Canine Kennel Cough”.  Signs for the Dog Flu include:

  • Fever (>103*F) 
  • Lethargy (more tired or depressed than usual)
  • Loss of Appetite
  • Sneeze/Cough (dry or wet, some dogs will cough so hard they may vomit or be painful)
  • Ocular or Nasal Discharge 

                  **If your dog shows any of these symptoms please contact your veterinarian**  

DIAGNOSIS: Dog patients can be tested for CIV through a nasal swab during symptoms or a blood test after symptoms are gone.  Kennel cough in dogs is a syndrome that can be caused by up to 10 infectious agents, some of which are bacterial (ex. Bordetella, Mycoplasma) and some viral (ex. Adenovirus, Coronavirus, CIV).  Coughing dogs can have 1 infection or a combination of infections.  Therefore, testing, in addition to a physical exam, is helpful in identifying the cause.

TREATMENT: Treatment is often supportive care and can be discussed between you and your veterinarian.  CIV is often treated with upper respiratory oral antibiotics and cough suppressants.  

PREVENTION: Vaccination and decontamination are the two main tools in outbreak prevention.  Currently most groomers, boarders and doggy daycares are requiring the CIV vaccine.  

  1. Hands and clothing are often the cause of spreading disease from one dog family to the next.  Shared dog bowls at restaurants and the floor of pet stores can also be a significant source of infection.  The virus can live on clothing for up to 12 hours and surfaces for up to 48 hours.  A diluted bleach solution with 10 minutes of contact time is the recommended cleaning tool.   Washing hands with soap for up to 30 seconds is recommended between petting different dogs. 
  2. Vaccination:  Vaccination remains our best method of prevention against CIV.  The current recommended vaccine is the Merck Bivalent low risk (double strain) H3N8 + H3N2 vaccine.  This vaccine is given as a set of two; the first vaccine is followed by a booster vaccine 2-3 weeks later.  The booster will provide immunity for up to 12 months.   A dog is considered protected from the vaccine 2 weeks following the booster (2nd vaccine).  Vaccinated dogs may still develop the disease but the course is much shorter and the symptoms much less severe. 


  • Keep your dog home and avoid activities/interaction with other dogs for at least four weeks.
  • Keep your dog isolated from other pets in the home including cats, guinea pigs and ferrets.
  • If your pet continues to cough 1 week after starting antibiotics and cough suppressants, please contact your vet.   
  • Be sure to frequently wash your dog’s toys and food/water dishes with soap and water.  Hands should be disinfected with soap and water or an alcohol-based hand sanitizer and clothing should be washed after exposure to dogs with signs of respiratory disease.