Dog Flu: Symptoms, Causes, and Treatment

Medically Reviewed by Kathleen Claussen, DVM on December 16, 2022
4 min read

Dog flu, or canine influenza, is a type of contagious disease in dogs. It’s usually not deadly, but it can make your dog pretty sick. 

The condition can affect any type of dog, no matter the age, breed, sex, or how healthy they are. It can also affect cats in some cases. Your pet can get this flu any time of year – it’s not seasonal like we normally think of these viruses.

The good news is, experts haven’t seen this type of flu affect humans at all. But it’s still important to know the risks if you have a furry friend.

Two type A influenza viruses, called “canine influenza viruses,” can infect dogs:

The H3N8 virus. This strain came from horses. It moved to dogs, becoming a canine influenza in 2004. The first cases of this strain in dogs happened in racing greyhounds in Florida.

The H3N2 virus. The canine influenza A (H3N2) virus is different from other influenza A (H3N2) viruses that are common in people during certain seasons. This one came from Asia and jumped from birds to dogs. It caused the 2015 and 2016 canine influenza outbreaks in the Midwest.

Dog flu is spread through respiratory droplets in the air when dogs: 

  • Cough 
  • Sneeze 
  • Bark 

It can also spread through contaminated: 

  • Water bowls 
  • Kennel surfaces 
  • Collars 
  • Humans who’ve touched a dog with the flu and then played with another dog

Signs of dog flu can be similar to kennel cough, another respiratory illness that dogs can get. Symptoms include:

  • Runny nose
  • Cough
  • Sleepiness
  • Fever
  • Discharge from the eyes
  • Decreased appetite

In some cases, your pet won’t have any symptoms at all. Less commonly, they might become severely sick. This can lead to pneumonia or death. But the number of dogs who die from dog flu is very small.

Call your veterinarian if you think your pet has dog flu or an infection from dog flu. 

They’ll check your dog for symptoms. The vet might suggest testing for H3N8 or H3N2 canine influenza.

If you plan to take your dog to the vet to check for dog flu, let them know beforehand. Since the virus is very contagious, your vet might have you follow special guidelines to keep other animals safe.

There is no cure for dog flu, but your pet’s vet can tell you how to keep your dog as comfortable as possible while they’re sick. Based on your pet’s symptoms, they may suggest:

  • Rest
  • Extra fluids to help them stay hydrated
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) to lower a fever
  • A body harness instead of collar to protect the throat
  • Nutritional support if you pet isn’t eating well
  • Antibiotics if needed for any secondary bacterial infections 

Your dog will usually get better in 2 to 3 weeks. But be sure to keep an eye on them. Dogs can sometimes get a bacterial infection from dog flu. This can make them even more sick.

The vet will also give you information about how to quarantine your dog while they recover. This helps lower the risk of it spreading to other pets. They’ll also tell you how you can disinfect your home to kill the virus.

In 2016, a few cats in an Indiana shelter got H3N2 canine influenza from dogs. This is how experts discovered that dog-to-cat and cat-to-cat transmission was possible.

Cats with dog flu showed similar signs including:

  • Congestion
  • A runny nose
  • Lip smacking
  • Increased saliva production
  • Lack of energy


The risk to humans is very low. But while there are no reported cases of dog flu in people, the Centers for Disease Control and Prevention (CDC) notes that influenza viruses constantly change. This means that it’s possible for the dog flu to one day infect humans.

The World Health Organization (WHO) monitors any changes in new human viruses. So far, the dog flu poses no threats to people.

You can take steps to lower their risks. Keep them away from kennels or other public areas with confirmed cases of the virus. If you come in contact with a dog that has it or one you think may have it, wash your hands, arms, and clothes right away. Do this before touching your dog to lower their risk. 

You can also get your dog vaccinated against both H3N8 and H3N2. You might want to consider vaccination if you live in an area with high levels of dog flu or travel to shows around the country.

Vaccination might also be a good idea if your dog tends to spend time around other dogs such as boarding in kennels, participating in doggy daycare, or playing at the dog park.