What is canine influenza?

Canine influenza, or the dog flu, is a highly contagious respiratory infection that is caused by two known strains of an influenza virus. The first, H3N8, appeared in the U.S. in 2004. The H3N2 strain quickly spread from the Chicago outbreak in 2015, and thousands of dogs have tested positive for H3N2 canine influenza since then.

Influenza viruses can quickly mutate and give rise to new strains that can infect new species. While both H3N8 and H3N2 came from species other than dogs, the H3N2 strain has now evolved to infect cats as well. Fortunately, there have been no reported cases of humans being infected with this strain.


How is the canine flu spread?

The canine influenza virus is easily spread through coughing, barking, and sneezing. Virus particles can be spread indirectly through objects, such as bowls, kennels, and collars. And, when people have been in contact with infected dogs, the virus can be carried on their clothing and spread to other dogs. The virus can remain in its infective state for up to 48 hours on surfaces, 24 hours on clothing, and 12 hours on hands, so appropriate disinfection techniques are crucial.


Is my dog at risk?

As with all new diseases, immunity has not had a chance to develop against this particular strain. Almost all dogs are susceptible to infection, and virtually all dogs exposed become infected. Factors that increase the risk of infection include:

  • Frequent exposure to other dogs
    • Daycare
    • Boarding
    • Dog parks
    • Grooming salons
    • Training classes
    • Shows
  • Young age
  • Old age
  • Pregnancy
  • Compromised immune system
  • Short, squashed muzzles (brachycephalic breeds)
    • Pugs
    • Bulldogs
    • Boxers
    • Pekingese

If there is news of a canine influenza outbreak in your area, stay safe and keep your dog at home.


What are the signs of canine influenza?

In most cases, clinical signs appear two to three days after exposure. Dogs are most contagious during the incubation period (one to five days after infection) and will shed the virus, even though they are not showing signs. Signs of canine influenza include:

  • Mild
    • Persistent soft, moist cough or dry cough (similar to kennel cough) lasting for 10 to 21 days, even with cough suppressants and antibiotics
    • Discharge from eyes
    • Sneezing
    • Lethargy
    • Anorexia
    • Fever
    • Thick nasal discharge, usually caused by a secondary bacterial infection
  • Severe
    • High fever
    • Pneumonia
    • Increased respiratory rate and effort

Cats can also become infected and may show signs of upper respiratory disease, such as nasal discharge, congestion, excessive salivation, and lip smacking.

Although most infected pets recover within two to three weeks, deaths have occurred, most commonly due to the development of pneumonia.


What is the treatment for canine influenza?

As with any viral disease, treatment consists of mostly supportive care. Good nutrition and nursing care are beneficial in helping an animal mount an effective immune response capable of fighting off the disease. Occasionally, secondary bacterial infections, pneumonia, dehydration, or other health factors can require additional treatments. Antibiotics, anti-inflammatories for fever reduction, or fluid therapy to correct dehydration may be necessary. During treatment, prevent transmitting this virus by isolating infected pets and others in the household for four weeks.


How can I prevent my dog from getting the flu?

If there is news of an outbreak in our area, be sure to stay home and limit contact with other dogs. Fortunately, a vaccination is currently available for dogs, protecting against both strains of the virus. But, at this time, there is no vaccination available for cats. Like all vaccines, the canine influenza vaccine does not guarantee that your dog won’t get the virus. But, vaccination can reduce the risk of your dog contracting influenza, and it may reduce the severity and duration of clinical signs if infected. If your dog’s lifestyle requires the kennel cough vaccine, the influenza vaccine should be part of her protocol as well, since they are similar infections.


Planning on traveling with your pet over the holidays? Or, will you be housing your dog in a boarding facility? Protect your furry friend and schedule an appointment for a canine influenza vaccination right away.