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Canine Influenza Virus – Causes, Symptoms, & Treatment

Canine Influenza Virus

What is Canine Influenza Virus?

Canine influenza is a highly contagious respiratory infection of dogs with sustained horizontal transmission caused by a novel influenza-A virus (canine influenza virus or CIV).

This disease, first diagnosed in greyhounds, has a low mortality rate, as with most other influenza infections (less than 8%) but has high morbidity (close to 100%).

This infection is distinguished from other viruses of the canine infectious respiratory disease (CIRD) group as it is thought to be a mutation from the H3N8 strain(original strain) of the equine influenza virus.

H3N8 strain mortality rate is 1%-5% with the most vulnerable group being dogs that have serious concurrent illnesses. That's certainly nothing to sneeze at. Remember the mortality rate of 1918 Spanish flu is only 2.5%.

There is another strain called H3N2 (avian strain) – which has jumped from birds to dogs. Dogs infected with the H3N2 strain seem to be at greater risk of developing more severe clinical signs however the risk of mortality is low.

Canine influenza can be contracted by being in close contact with other dogs (like in dog parks, boarding kennels, doggy daycares, etc), tactile nose/mouth contact, through contaminated objects (food and water bowls, toys, leashes, and collar) and nasal secretions via airborne droplets (through coughing, sneezing or barking).

Even though there is no evidence that canine flu viruses pass on to humans, influenza viruses can mutate rapidly, and there is a dangerous possibility that at some point in the future, genes that govern infectivity in dogs may mutate and may infect humans.

Symptoms Of Canine Influenza Virus

Just like when you get the flu, your dog also sneeze, have a runny nose, and cough. Canine flu symptoms resemble symptoms of tracheobronchitis ("kennel cough").

  • Fever (often 104-105oF).
  • Productive cough (‘moist’) or non-productive (‘dry’).
  • Sneezing.
  • Runny nose.
  • Purulent nasal discharge.
  • Eye discharge.
  • Labored breathing.
  • Anorexia.
  • Malaise.

Treatment Options For Canine Influenza Virus

  • Treatment is general supportive care (rest and fluids).
  • Broad-spectrum antibiotics.
  • Cough suppressants.
  • Quarantine with hospitalization for the more severe/complicated cases.

Home Remedies For Canine Influenza Virus

While the best prevention is to avoid high-risk locations or contact with an infected animal that is not always possible.

When potential exposure cannot be avoided, proper vaccination can prevent or reduce the symptoms, decrease the duration of the illness and prevent the spread.

How to Prevent Canine Influenza Virus?

There is a vaccine for the H3N8 strain and for the H3N2 strain, and a bivalent vaccine that covers both strains in one shot is also available.

Canine influenza may persist in the environment for a day or two, 12 hrs in hands, 24 hrs on clothing for up to 24 hours. Survival for 24 hrs is possible on surfaces like stainless steel and plastic.

Many disinfectants commonly used in veterinary hospitals and shelters can easily kill the flu virus (aldehydes, phenols, and bleach solutions at a 1 to 30 dilution, potassium peroxymonosulfate, or quaternary ammonium compounds).

Affected Dog Breeds Of Canine Influenza Virus

Boston Terrier, French Bulldog, Boxer, Pekingese, Pug, Shih Tzu, Brachycephalic Dog Breeds

Additional Facts For Canine Influenza Virus

The onset of clinical signs after infection for H3N2 is 2 - 3 days, while those infected with H3N8 may start showing signs between 1 - 5 days.

H3N2, H3N8 peak virus shed: 3-5 days post-infection; however, longer shedding times of up to 24 days (H3N2) have been identified in dogs.

Usually, the severity of canine flu is high. Most dogs recover within 3 weeks; still, they can continue to be contagious to other dogs for up to 24 days( H3N2) and 14 days for (H3N8).

Canine influenza virus symptoms can be:

  1. Mild:
  • Symptoms are similar to kennel cough but persist longer.
  • Typically moist cough, nasal discharge.
  • Dry cough (rarely).
  • Symptoms: 10 to 30 days and usually will go away on their own.
  • Dog flu treatment reduces the duration or severity of symptoms.
  1. Severe:
  • High fever (104-105oF) and develop signs very quickly.
  • Pneumonia.
  • Blood cough and trouble breathing (if the virus affects the capillaries in the lungs).
  • Secondary bacterial infection (such as bacterial pneumonia) can further complicate the situation.

When To See A Vet For Canine Influenza Virus?

Contact your vet for vaccinating your pets. The most effective way to protect against canine influenza is through vaccination.

These are lifestyle vaccines (non-core vaccines). When you are dogs are expected to mix with large numbers of other dogs such as in kennels, dog parks, etc or if you frequently take your dog outdoors or when traveling to high-risk places, vaccination is recommended.

Dog owners should consult with their veterinarian as soon as they notice the symptoms as some conditions can be very serious (and possibly fatal).

Dog Food Suggestions For Canine Influenza Virus

Dietary management of canine flu:

  1. 70% animal-based protein and fat (meat, organ meat, cottage cheese, eggs, yogurt) and 30% low glycemic (low-sugar) vegetables - Carrots, Greens (spinach, kale, collards, beet).
  2. Brown rice, lukewarm (never hot) chicken soup with Low sodium or chicken breast and cooked vegetables are perfect for the ailing pup. Add calcium in the form of calcium carbonate or calcium citrate at 900 mg per pound (in a home-cooked diet).
  3. Add a couple of spoonfuls of salmon, tuna, mackerel, anchovies, or another fish product to your dog’s food.
  4. Too much-canned fish is bad for a sick pup. A small quantity to tempt an unwell pet to eat is usually ok.
  5. Raw diet:
  • 50% - Good meats include ground pork, beef, chicken, turkey, or green tripe (cow stomach or unbleached tripe).
  • 50% - Add raw meaty bones (one-half of the diet for the calcium).


Does my dog need the flu shot?

This depends on your dog’s risk of exposure, lifestyle, and prevalence of the virus in the region. It is always good to check with your vet if vaccination is appropriate for their dog.

Keep informed about outbreaks of infections in your community. So that, if there’s canine influenza or any other kind of infection, you’ll get updates about how to keep your dog and yourself safe until the outbreak passes.

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