Everyone dreads the onset of flu season; as temperatures begin to dip and the weather stays cooler through the winter months, the flu virus is able to thrive and spread rapidly through communities. But while many worry about the flu impacting themself or their family, they don’t realize that their dog could be at risk year-round, too.
So, can dogs get the flu? The short answer is “yes,” and there have been multiple widespread outbreaks across the United States in recent years. The H3N2 strain of canine influenza first appeared in U.S. dogs in 2015, sparking large outbreaks that quickly spread from Chicago to other states through kennels, shelters, and dog shows. Since then, the virus has reappeared in waves, with outbreaks occurring all over the United States in various environments. While H3N8, an older strain, is no longer commonly detected, H3N2 remains a risk in communities where dogs gather, and new clusters of respiratory illness continue to emerge every year.
Here’s what you need to know about the canine influenza virus, or the “dog flu,” to keep your pup safe and healthy.
How Serious Is Canine Influenza?
The severity of canine influenza varies from dog to dog. Some will show few symptoms, while others are at risk for pneumonia. In most healthy adult dogs, the illness is uncomfortable but manageable with supportive care, and most dogs will fully recover within a few weeks.
However, canine influenza can sometimes progress to more serious complications. Dogs with weaker immune systems — such as puppies, seniors, or those with chronic health issues — are at higher risk of developing pneumonia, which can become life-threatening if untreated. Severe cases may also result in dehydration, difficulty breathing, and, in rare instances, death. Because the virus is highly contagious and spreads easily in group settings like kennels and dog parks, even mild cases are important to take seriously.
Canine influenza also doesn’t follow a typical “flu season” like we are used to when we get sick. New outbreaks can begin at any time, so if you suspect your dog has been exposed to the canine influenza virus, your best course of action is to take the precautions of cleaning everything that comes in contact with your pet, isolating your dog from other dogs, and consulting with your veterinarian.
Dog Flu Symptoms to Watch Out For
Common Symptoms of Mild Cases of Dog Flu
- Coughing, usually persistent, dry, or honking in nature
- Sneezing
- Runny nose (nasal discharge)
- Fever, which is often mild (101–103°F), but sometimes higher
- Lethargy, including reduced activity or reluctance to move
- Loss of appetite
- Eye discharge (conjunctivitis), which is watery or thick
Less Common or Severe Symptoms
- Difficulty breathing or rapid breathing
- Pneumonia, which can occur in severe cases, especially in puppies, the elderly, or immunocompromised dogs
- Vomiting or diarrhea
- Dehydration from fever or reduced water intake
Symptoms can vary depending on each individual dog and the severity of their infection. In most cases, symptoms will appear within two to four days after a dog has been exposed. Once symptoms begin, it’s important to monitor them closely and bring them in for an examination with your vet. Intervening early makes sure that your dog gets the supportive care that they need and allows your veterinarian to take action before the illness progresses into something more dangerous, like pneumonia.
Is Dog Flu Contagious to Other Dogs?
Canine influenza is highly contagious among dogs. They can pass it among themselves from contaminated objects like toys, water bowls, and leashes, as well as through direct contact. Additionally, people can transmit it between dogs, though there’s no evidence that people can contract it.
Who’s at Risk?
All dogs can be at risk of contracting canine influenza, but there are a few factors that may put them at a greater risk of falling ill with the dog flu. To start, many outbreaks are linked to congregate settings for dogs (shelters, daycares, boarding), as these environments are considered high-risk environments due to close contact, movement of dogs in and out, etc. Dogs who live in or visit these environments may be at a greater risk of contracting the dog flu in the event of an outbreak at their facility. Worse, a dog doesn’t have to exhibit the symptoms to infect another dog because it can take 2-4 days for the symptoms to show, though they still “shed virus” via their nasal secretions.
There have previously been reported outbreaks of canine influenza in show settings as well. In May of 2017, dogs from two dog shows in Leland, Florida, and Perry, Georgia, were diagnosed with the disease, and University of Florida College of Veterinary Medicine officials confirmed the outbreak of the canine influenza A virus.
In 2021 and 2022, Los Angeles County experienced a relatively large outbreak of H3N2 with over 1,000 reported cases linked to boarding kennels, day care facilities, and shelters. Other mysterious canine respiratory cases have been documented more recently, so dog owners are urged to practice preventative measures and keep their dogs away from group settings if they are displaying signs of any respiratory illness.
Important to Note: Even though no U.S. state requires the canine influenza (CIV) vaccine, a lot of pet-care facilities do. If your pet hasn't been vaccinated or can't get the vaccine, it's a good idea to check with the facility beforehand to see if they accept veterinary medical waivers. This will help prevent any problems on the day of service.
Can Dogs Get the Flu from Humans?
While canine influenza can spread very rapidly in communities of dogs, the good news for pet owners is that the type of flu that affects us humans is very different from the flu our dogs can become sick with, so you don’t need to worry about passing your illness to your pup or vice versa. So, don’t worry, those extra snuggles with your sick dog are totally safe!
How to Prevent Canine Influenza
As veterinarians, we’re closely following this virus, and we recommend the following protocol to protect your dog.
- Talk to your veterinarian about the canine influenza vaccine. In a release from Merck Animal Health, “Dogs at risk should be vaccinated at least yearly with both influenza strains, H3N8 and H3N2,” says Ronald Schultz, Ph.D., professor of pathobiological sciences at the University of Wisconsin School of Veterinary Medicine. High-risk dogs include those who attend dog shows, boarding facilities, and doggy day care.
- Disinfect crates, bedding, toys, and anything else that comes in contact with your pet. Germs can survive for 24 hours on hard surfaces, so you’ll want to clean everything your pet touches.
- Wash your hands between dogs. While humans are not able to contract the virus from the dogs, you can spread it from one dog to another.
- Isolate infected dogs for 21 days to ensure the disease is passed. After the Chicago outbreak, tests confirmed that some dogs were still carrying the virus for up to 21 days after diagnosis.
Options for Canine Influenza Treatment
Once your veterinarian has confirmed a positive diagnosis of canine influenza for your dog, they will focus primarily on supportive care and management of any present symptoms to allow your dog’s immune system to successfully fight off the infection.
A few of the most common treatments for dog flu that a veterinarian may employ include:
- Fluids to prevent dehydration
- Cough suppressants or anti-inflammatory medications to ease discomfort
- Nutritional support, such as soft or warmed food, to encourage eating
- Antibiotics are used if a secondary bacterial infection, like pneumonia, is suspected
Is There an At-home Treatment for Dog Flu?
Whether or not you can treat the dog flu at home will depend on the severity of your specific dog’s illness, as well as what symptoms they are exhibiting and their overall health status. If your dog is relatively healthy and only showing mild symptoms while still eating and drinking normally, they may be able to be treated at home. Puppies, senior dogs, and dogs with more severe symptoms or those that are not acting like themselves should be seen by a veterinarian, and owners should not attempt to treat them at home.
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