Canine Influenza – Can Dogs Get the FLU?

Canine Influenza – Can Dogs Get the FLU?

From the Desk of Dr. Dennis Voorheis


In my last blog entry, we talked about the pros and cons of our local dog parks and in that piece, I briefly touched upon the topic of canine influenza with the promise of a blog entry dedicated entirely to that subject. So, this time around, let’s chat about the possibility of “canine flu”. Our obvious starting point for this discussion would be “can dogs actually get the flu?”. The short answer is YES but as we all know, I’m not one to simply give a short answer and be done with it. The longer answer is an entire blog, and one that comes with recommendations about vaccination at the end. There are two influenza virus strains that affect dogs, H3N8 and H3N2. Both cause similar symptoms in dogs that are likewise similar to a host of other respiratory diseases.

Let’s begin with some background for a bit of base line knowledge. The Influenza A virus, which the H3N8 and H3N2 are subtypes of, can cause infection in many different mammalian species including humans and birds. It exists in multiple subtypes and these subtypes mutate and thus the need to get our human FLU shots every year. Canine Influenza Virus (CIV) was first identified in 2004 in a group of Greyhounds associated with Florida racetracks. The virus was identified as a genetic variant of the H3N8 equine influenza that gained the ability to infect dogs. The key change was an ability of H3N8 to move from dog to dog. The newer influenza virus, H3N2, is derived from an avian strain that gained the ability to infect dogs and is transmitted from dog to dog. It can rarely also affect cats. It was first reported in 2006 in South Korea and appeared in the Chicago area in 2015 where it caused a large outbreak. With both types of CIV, infected dogs shed virus for two days prior to symptoms.  With the H3N8 they continue to shed virus for 4 to 10 days after signs begin. Dogs infected with H3N2 shed virus for up to 24 days after signs begin even when they no longer appear sick. That is a significant amount of opportunity to spread the virus. So far, the affected outbreaks are limited and isolated and this is not an epidemic in Los Angeles County at this point in time.



The virus was first detected in California in March of 2015 in Orange County and then again in July of 2015. A vaccine first became available in November 2015. In March of 2017, CIV H3N2 was identified in dogs in Los Angeles County. A total of 50 dogs were exposed to the virus, including 35 sick animals. PCR testing confirmed H3N2 in 5 of those dogs, the remainder of the sick dogs were assumed to have H3N2 because they were in the same group of dogs and had the same signs.  Two dogs died, however they also had other unrelated illness that contributed to their deaths. The rest of the sick dogs have now recovered. There was another case out of the San Bernardino shelter that has been confirmed and isolated and no new cases have been confirmed.

Canine Influenza (CIV) usually causes mild to moderate disease in dogs. The signs are fever, coughing, sneezing, nasal discharge, lethargy, and loss of appetite. Some dogs have no symptoms at all. Some of the more severe and fatal cases have pneumonia. It is spread through direct contact with respiratory secretions from infected dogs and by contact with contaminated objects such as toys, bedding, leashes, collars, cages and floors. The virus can survive for 1 to 2 days on floors and cages.

The above described symptoms are seen every day by veterinarians in Los Angeles County.

They comprise a group of diseases bunched into one of two common terms, upper respiratory disease or kennel cough. Most of the time, diagnostics such as PCR testing to determine a cause of a runny nose or cough, are not performed. The “sicker” dogs are usually the dogs that get more diagnostics performed on them. If you suspect that your dog may have these signs and may have been exposed, please call for an appointment to see one of our veterinarians. Please let the front office know at the time of making the appointment that you think the dog may have an infectious cough, sneeze or upper respiratory issue. At the time of your arrival, if it is not too hot, you may be asked to wait outside in your car until we can admit you. Alternatively, you may be brought in through a side entrance and placed immediately into an exam room to avoid cross contamination in the lobby area. Please do not wait in the lobby with a dog that you suspect may have an infectious upper respiratory issue as these can be highly contagious for other animals.

One of the advantages of being a “seasoned” veterinarian, is that I have been around long enough to have seen emerging viral diseases change the medical landscape. Parvo viral enteritis, feline immunodeficiency virus and influenza are just a few examples of how viral diseases can change the medical landscape we practice in. Frankly, I’d prefer not to be part of another viral epidemic like the one I was witness to in the late 70’s/early 80’s with the parvo virus. Due to the relatively brief period of time influenza lasts outside the body, it is unlikely to end up as significant a problem as the parvo virus is. However, the epidemic that hit Chicago in 2015 certainly was devastating and the potential exists that it could affect us in the same way. So far, we appear to have dodged a bullet so let’s hope it stays that way. Vaccination of at risk groups dogs is certainly the most “common sense” approach to prevention at this point.  

There are some reasonable recommendations that have resulted from the canine influenza topic which are being made by our public health veterinarians. There are groups of dogs that are “at risk” dogs. These are dogs that are in highly social situations such as:

  1. Dog shows
  2. Agility, obedience and other trials
  3. Dog Parks
  4. Doggy Day Care
  5. Boarding facilities
  6. Grooming facilities
  7. Any other group or activity where dogs are interacting with other large numbers of dogs with unknown exposure or vaccination histories.

The recommendation is that the dogs that are in these situations should be vaccinated against CIV. We have not yet made the vaccination a requirement to use our grooming or boarding facilities at WBAH, but that may very well change as we monitor what is happening at the county level. A second question that will come up is, “is it safe to vaccinate?” That answer is yes. The vaccine is a killed vaccine, given as a set of two shots, three weeks apart. It is my recommendation that if your dog participates in any of the above social activities, he/she be vaccinated against CIV. If you would like to discuss this topic in more detail, please schedule an appointment with one of our veterinarians and allow them to provide you with more detailed information.

Next up……. The trending grain free diet.

Until next time,

Dr. Voorheis


  1. Joy

    Thanks Dr. Voorheis!!! I had heard about dog flu, but wasn’t too sure of what the reality of the situation was. This blog gave excellent, educated, and clear information about the dog flu!!! I will pass it on 😉

  2. Kirsten Pickus

    Thank you, Dr. Voorheis. I’ve been waiting for your thoughts about the CIV vaccinations and am very appreciative of your recommendation.

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