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What Dog Owners Need to Know About Dog Flu

In this internet age, it seems that we are we are constantly bombarded with dire warnings about flesh-eating bacteria, the collapse of Western civilization, and my personal favorite, zombie apocalypse. Most of us try to avoid the panicked Facebook posts and Twitter feeds and usually manage to stay above the panicked fray however real the threat may or may not be.

But a virus that could harm our beloved furry canine soul mates? Now that’s hitting below the belt and sends us running for the hills — or at least to Google and the phone to call our family vet and ask for help managing our fears!

So when The Mercury News, along with multiple other news agencies and internet media sources, announced last month that several cases of “deadly dog flu” had been confirmed in the Bay Area, our phone lines lit up, and I knew that I had to prepare my team pronto.

What is dog flu?

Canine influenza or dog flu is a highly contagious respiratory infection of dogs that is caused by influenza A virus. In the United States, canine influenza has been caused by two influenza strains. The first strain reported in the United States in 2004 was H3N8 influenza A virus. This strain is closely related to the virus that causes horse influenza, and it is thought that the equine influenza virus mutated to produce the canine strain, perhaps due to overuse of the flu vaccine in domestic horses. In 2015, a flu outbreak that started in Chicago was caused by a separate canine influenza virus, H3N2. The strain causing the 2015 outbreak was almost genetically identical to an H3N2 strain previously reported only in Asia. This H3N2 strain is believed to have resulted from the direct transfer of an avian influenza virus — possibly from among viruses circulating in live bird markets — to dogs.

As often seen in human flu infections, two clinical pictures have been seen in dogs infected with the canine influenza virus — a mild form of the disease and a more severe form that is accompanied by pneumonia.

What are mild form signs?

Dogs suffering with the mild form of canine influenza develop a soft, moist cough that persists for 10 to 30 days. They are usually lethargic and have reduced appetite and a fever. Sneezing and discharge from the eyes and/or nose may also be seen. Some dogs have a dry cough similar to the traditional “kennel cough” caused by Bordetella bronchiseptica/parainfluenza virus complex bacterial infection which is often mistaken for K9 flu.

What are severe form signs?

Dogs with the severe form of canine influenza develop much higher fevers (104º F to 106º F) and have clinical signs of pneumonia, such as increased respiratory rates and trouble breathing and walking. Rarely do these flu infections present with symptoms of vomiting or diarrhea seen in many human infections.

How is it spread?

Just like the human flu, dog flu is spread through close contact in highly populated areas such as dog parks, boarding, grooming and day care facilities as well as pet hospitals. Sneezes, coughs, shared water dishes, and toys can all be to blame spreading infection. Contact from pet owners or health care workers who have been handling flu-infected dogs can spread the disease if they don’t take precautions to effectively clean their hands and clothing.

What are the risks of exposure?

Because this is still an emerging disease and dogs in the United States have not been exposed to it before, almost all dogs, regardless of breed or age, lack immunity to it and are susceptible to infection if exposed to the active virus.

However, the risk of any dog being exposed to the canine influenza virus depends on that dog’s lifestyle. Dogs that are frequently in contact with other dogs — for example at boarding or day care facilities, dog parks, grooming salons, or social events with other dogs present — are at greater risk of coming into contact with the virus if there is an outbreak.

Also, as with other infectious diseases, extra precautions may be needed with puppies, elderly, or pregnant dogs, and dogs that are immune-compromised. Dog owners should talk with their own veterinarian to assess their dog’s risk.

As with human flu infections, there are rare deaths associated with the flu virus, but the fatality rate is low (less than 5 percent) and most dogs recover in two to three weeks. It’s important to note that K9 flu is not contagious to humans (nor are human flu strains contagious to dogs). There is some evidence to suggest that flu strains can be contagious to cats, so ask your family vet if this is a concern in your family.

Should you vaccinate your dog?

Several vaccines are available for your dog, and many veterinary clinics are using the canine bivalent flu vaccine that protects against H3N8 and H3N2 infections. It has been clinically proven to significantly reduce the severity of influenza and the length of time that a dog is sick but does not prevent the illness altogether. The vaccine does not work if your dog is already exposed to the flu and must have a second booster one to two weeks after the first shot is given before it becomes effective. Each shot can cost up to $100 with an annual booster needed.

Although side-effects of the vaccine are not particularly common, they’re more likely to affect smaller breeds. The most common side-effect is fatigue, but many dogs experience fever, vomiting, diarrhea, respiratory distress, facial swelling, pale gums, and pain at the site of the injection.

At Creature Comfort Holistic Veterinary Center, we practice holistic/integrative medicine. Our clients trust us to speak honestly with them about the pros and cons of vaccinating dogs for the flu virus. Our team asked why were clients so scared? What were the facts in this “epidemic”? Would vaccination promote a false sense of security encouraging pet owners to take exposure risks with their pets if they feel they are “safe” from contracting the virus? Could the vaccine actually lower the dog’s ability to fight off the virus naturally?

Ultimately it was up to the pet owner to make the choice for their own beloved dog, but we agreed that it was much better medicine to spend the time discussing each individual client’s fears, their dog’s exposure risks, and health concerns before making a recommendation to vaccinate their pet. Most of our clients choose not to vaccinate but to stay vigilant and keep their pets exposure to a minimum while naturally boosting their immune systems with a healthy diet and natural immune boosting supplements.

Our clients understand that if their dog’s situation changes, they can come to us to receive the bivalent flu virus vaccine that we keep on hand for those dogs that truly need the extra vaccine protection due to age and other risk factors.

What’s right for my dog?

With any decision regarding your pet, this is a personal one that you have to make based on your comfort level. But it is imperative that you make these decisions based on facts, not fear. We all know the media tends to promote scary, eye-catching headlines. Do your research the way we do — through reputable sources directly involved with this issue (links to several excellent web sites are included to help you educate yourself on these issues). Always remember to breathe through the fear and try to act and not reactr. This practice will serve you well when the next epidemic rolls into town.

If you have more questions about dog flu, are uncertain if your dog is at risk, or wonder if the vaccination is needed/appropriate for your four-legged friend, please have a conversation with your trusted family veterinarian. He or she will help you decide the best way to protect your best friend.

Helpful Resources

Jenny Taylor, D.V.M., founded Creature Comfort Holistic Veterinary Center in 2001 in Oakland. Creature Comfort offers traditional Western medicine and surgery integrated with holistic therapies. Visit for more information.

Are you a San Francisco Bay Area veterinarian who would like to write an article for the Ask Dr. Dog column, which is authored by guest veterinarians practicing in the Bay Area? Bay Woof is accepting submissions. Send email to





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Main article photo by: Photo by istock/Photoboyko