Influenza In Dogs – The Dog Owners Guide

If you are a dog owner and watch the news, the chances are you’re pretty worried right now. Stories of dogs dying from canine influenza are alarming, to say the least, and may leave you with more questions than answers. If you’re left wondering if it’s safe to board your dog or send them to doggy day-care, then this article aims to give you those answers and help you understand the facts behind this unpleasant (but not necessarily life-threatening) condition.

Flu Fact
  • Your dog can NOT infect you with the influenza virus

An Overview of Canine Influenza

Before getting into the specifics, here is an overview of canine influenza (CI).

Thinking of dog flu in a similar way to human flu is quite helpful because both infections have a lot in common. For a start both forms are easy to catch – usually because a sneeze or cough seeded an aerosol of infectious particles into the environment.

Just like human flu, canine influenza can infect any dog that is not immune to it. Young or old, healthy or sick, any dog that comes into contact with the virus for the first time can become ill.

What dogs are most vulnerable to canine influenza?

Just like people, how sick a dog becomes depends on the strength of their immune system. A healthy, vigorous adult may fight the disease off and not become ill, (as happens with 20% of the dog population). Those with weaker immune systems such as those who are very young, elderly, pregnant, or ill with another condition, are more likely to become ill.

Treatment for canine influenza

The cause of canine influenza (CI) is a virus. There is no “cure”, (antibiotics kill bacteria rather than viruses), and so treatment consists of love and care from the owner in mild cases, to supportive care (intravenous fluids and antibiotics against secondary chest infections) for the severely ill.

Preventing influenza in dogs

There is a vaccine to a similar (but not identical) viral strain of this latest outbreak, but experts cannot say if it will protect on this occasion. Therefore, this is a case of prevention being better than cure: hence, in regions where infection is rife, the advice is not to let dogs mingle.

The Unseen Enemy

This outbreak of influenza in dogs hit the news because so few dogs have immunity. This virus is a mutation, which means it’s new and the dog’s immune systems do not recognize it. Much like reading a foreign language for the first time, the dog’s defenses don’t know how to react. Each dog has to learn to “read” the virus and figure out how best to defend against it. Some are quick learners and fend off infection, whilst others struggle and the dog becomes sick.

Flu Fact
  • The H3N2 is a mutated form of avian flu, whilst H3N8 is a mutation of horse flu.

The H3N2 strain In Dogs

The cause of this outbreak is a viral strain called H3N2, which originates from South Korea. (At the time of writing, no one knows how it entered the States.) If the name sounds familiar that’s because a close relative, the H3N8 virus, has been around since 2004.

A vaccine is available based on the H3N8 strain, but it is too early to tell if this gives cross protection against the newer, H3N2 strain.

How the flu virus spreads in dogs

When an infected dog coughs, he propels an aerosol of infectious particles into the air. This then settles onto surfaces and acts as a source of infection for the next dog that sniffs there. Flu viruses are hardy and able to survive for quite some time on infected surfaces and clothing, which both act as reservoir of infection.

Of course, close contact between dogs, such as at doggy day care, means more nose-to-nose sniffing, which is the easiest and most direct way for the virus to spread.

The Symptoms of Canine Influenza

OK, so your dog visited a park where dogs with flu have played. What signs or symptoms should you be on the alert for. Remember what it felt like the last time you had flu? Well dogs are no different. The general signs are:

  • Lack of energy (due to those achy muscles and a stuffy head)
  • Poor appetite (who wants to eat when they ache all over?)
  • Runny nose and streaming eyes
  • Honking, harsh cough
  • Fever

Complications set in if the virus overcomes the lungs’ defence mechanisms. These can lead to a secondary pneumonia, which may be life-threatening, but happens in less than 10% of cases. The signs are those of a very sick dog and include:

  • Extreme tiredness and dullness
  • Rapid, laboured breathing
  • Vomiting
  • Refusing food and water
  • High fever

Infection timeline for influenza in dogs

If your dog went to the park yesterday, it is too early to tell if he has picked up flu. Here is the typical infection timeline:

  • Signs of flu start usually start 2 – 3 days after your dog meets an infected one
  • The signs of mild flu may last anywhere up to 3 – 4 weeks
  • The dog is most highly infectious to others 3 – 4 days after infection, and remains so for about 2 weeks.

Treatment of Canine Influenza

If your dog starts coughing, what should you do?

– Contact your vet and isolate your dog.

– Tell the vet what the symptoms are and be guided by their advice.

Be aware, there is no “cure”, it is a matter of managing symptoms such as aching muscles, and making sure the dog is eating and drinking. Dogs that deteriorate and have suspected pneumonia will need more intensive treatment and be admitted to the veterinary clinic.

Care of the seriously ill dog includes intravenous fluids to prevent dehydration, anti-inflammatory drugs to decrease lung damage, and aggressive antibiotic therapy.

Diagnosis of Canine Influenza

Yes, there are tests for canine influenza, but it may not be cost efficient to run them. This is because putting a label on the symptoms isn’t always necessary or helpful, when it comes to therapy.

However, tests can be helpful in some circumstance–for instance if the vet isn’t certain flu is responsible for the cough or in a kennel situation where many dogs are at risk. The tests most commonly run are:

  • Nasal or throat swabs – to detect the actual virus. These work best in fresh cases showing signs for less than seven days.
  • Blood tests – these look for antibodies (the dog’s immune response) against the virus. This test works best when signs have been present for at least seven days.

Control and Prevention of Influenza in Dogs

In theory, if all dogs are isolated and didn’t mix for one month, it could bring an end to the flu outbreak. This is because isolation deprives the virus of the chance to spread from dog to dog within the period of time it can survive in the environment.

Whilst it isn’t practical to stop all dogs going outdoors for four weeks, a sensible option during an outbreak is to limit social contact between dogs. This has the double benefit of making your dog less likely to acquire infection, and stops infected dog sharing the bug.

This is the logic behind advice in the news and the like, not to board dogs, attend doggy day care, or go to grooming parlors. However, ultimately the decision is up to you, the dog owner based on the risk posed to your individual pet.

Avoid Mixing

If putting your dog into day care or the kennels is unavoidable, your dog may not catch flu but there is a statistically greater risk (because of mixing with dogs) they will contact the H3N2 virus.

If your dog is fit and well, whilst flu is unpleasant, it is unlikely to be fatal. However, if your dog is elderly, or has a heart condition, then the risk of serious complications is higher. As an owner you need to balance these risks to make your decision.

Of course, as a responsible owner if your dog coughs then you must isolate them until the cough has gone, and NOT attend a parlor or day-care (or even go to the park) until it is proven they don’t have flu and no longer pose a risk to others.


The good news is many common disinfectants kill the H3N2 virus. A simple dilute bleach solution (1 part bleach to 30 parts water) or a quaternary ammonium compound is sufficient to disinfectant food bowls, walls, floors, and dog beds.

Also, after petting a dog washing your hands with soap and water gets rid of the virus from your skin.

Visit the Veterinarian

And finally, if your dog starts to cough and you suspect flu, contact your veterinarian, and explain the symptoms over the phone. In outbreak areas many veterinary clinics now see suspected flu cases in the parking lot or another designated area, to reduce the risk of contamination in the waiting area or clinic.

In addition, there may be a designated veterinarian seeing flu cases. This veterinarian wears disposable protective clothing to examine each patient, and changes clothes before going back to their regular duties. By alerting the clinic to your suspicion, it helps the clinic manage each case responsibly so as to reduce the risk to other patients.