Sad dog lying on bed covered with blanket

Dog flu: the importance of vaccinating your pets

Can dogs get the flu? Yes, they can, and here’s what you need to know

Did you know dogs can get the flu, too? Yes, just like their owners, dogs can contract canine influenza, causing similar symptoms (although human and dog flu viruses are different – there is no evidence of the spread of canine influenza viruses from dogs to people1).

Canine influenza is a relatively new virus. The first of two existing strains of canine influenza was identified in 2004 and the second in 2007.1 But it’s becoming a growing concern.

These days most pet diseases are prevented with vaccination and it’s easy to take the wonder of immunity for granted. Basically, immunity can be summed up with one word: prevention.

From a veterinarian’s perspective, it’s always easier to prevent a disease rather than treat it. Vaccines stimulate your pet’s own immune system to make antibodies that provide long-term protection from various infectious diseases. Vaccines are usually in the form of an injection, though some oral or nasal alternatives are now available.

Pets start their vaccination programs early on (usually at around seven weeks of age) to prevent a number of diseases, and these vaccines work very well. In addition to dog flu, commonly recommended canine vaccines include rabies, distemper, parvo, hepatitis, bordetella, leptospirosis, Lyme, and parainfluenza.

If you’re skeptical about how dogs and cats contract diseases and viruses, it’s surprisingly easy. Most domestic pets are social creatures. Dogs may come into direct contact with other dogs when they visit dog parks or doggie daycares, while other dogs enjoy a good sniff (in some very choice places) during their daily walks – places where sick dogs may have visited.

All these forms of potential contact provide countless opportunities for viruses to be transmitted from one animal to the next. Throw in the interactions at boarding, grooming, daycare, and at the vet’s office and it’s virtually impossible for pet owners to prevent their dogs from coming into contact with germs.

Unfortunately, there are some extremely unpleasant bugs out there. This brings us back to prevention as opposed to treatment. A population of vaccinated animals helps limit the spread of diseases – including dog flu.

2015’s outbreak of the new strain of canine influenza, H3N2, demonstrated just how quickly viruses can spread. Thousands of animals contracted CIV H3N2 dog flu in the Midwest during the original outbreak, and in less than one year, this new flu strain was confirmed in over half the country. Since this is a relatively new pathogen, most dogs are susceptible to infection because they have no natural or vaccine-induced immunity when first exposed to the virus.

What is canine influenza?

Canine influenza, or dog flu, is a highly contagious respiratory infection caused by an influenza A virus. Here in the US, canine influenza has been caused by two strains classified as H3N8 and H3N2. H3N8 was first discovered in 2004 in the US.1

The infection is spread through the germs released while coughing, barking, and sneezing, or through contact with any contaminated objects, including hands, clothes, and any surface dogs come into contact with. The virus can remain alive on these surfaces or clothing or hands for several hours.

To add to the complexity, dogs are most contagious during the two- to four-day incubation period but exhibit no symptoms during this time. So exactly how and where your dog caught the virus could prove difficult to determine.

What are the symptoms?

Canine influenza symptoms include coughing, sneezing, lethargy, and loss of appetite. Infected dogs may present with one of two different syndromes:

  1. Mild. The more common of the two, with symptoms including coughing and nasal discharge. Some dogs are sick with dog flu for weeks.
  2. Severe. Infected dogs will have a high fever with symptoms developing very quickly. At worst, these include intense coughing, weakness, lethargy, and trouble with breathing. In rare cases, the dog can develop pneumonia.

How often should dogs be vaccinated against dog flu?

  • Puppies (from seven weeks of age) receive two doses separated by two to four weeks
  • Booster vaccinations (single dose) should be performed on a yearly basis thereafter


  1. Key Facts About Canine Influenza (Dog Flu) | Seasonal Influenza (Flu) | CDC.

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