Have you ever wondered, “Can dogs get the flu?” As it turns out, they can. Canine influenza virus (CIV) is a dog-specific strain of flu that can spread from one dog to another. Integrative veterinarian Dr. Julie Buzby outlines the transmission, symptoms, diagnosis, treatment, and prevention of dog flu.
If you’ve ever had the flu, you know how miserable it can be. It would be great if our dear dogs didn’t have to go through that, too, but unfortunately, they are susceptible to their own strain of the flu. Canine influenza is highly contagious and can make your dog feel crummy. Thankfully, though, it is rarely fatal.
Can dogs get the flu?
Dogs can catch the flu—canine influenza, more specifically. Canine flu is a respiratory illness caused by influenza viruses H3N2 and H3N8, which are both strains of influenza A. H3N2 canine influenza originally came from birds, and H3N8 originated from horses. Both strains are now transmissible among dogs and can even infect cats.
Researchers discovered the canine influenza virus (CIV) relatively recently. It was first diagnosed in racing Greyhounds in 2004, believed to have originated from H3N8 equine influenza. The virus quickly spread to pet dogs and shelter dogs, and has been found throughout most of the country ever since.
Can dogs get the flu from humans?
While rare, it is possible that human influenza viruses can infect dogs. Studies have detected evidence of human influenza viruses in dogs, but infected dogs may not show any symptoms. Human influenza viruses also do not seem to persist long in the dog population.
This may sound worrisome, but remember, your dog is a lot more likely to get the flu from another dog than a person. If you are sick, just continue taking the normal precautions that help decrease the spread of disease to others (washing your hands, covering your sneezes and coughs, etc.).
Can humans get the flu from dogs?
It is highly unlikely that humans would catch the flu virus from dogs. Even so, it is advisable to practice good hygiene, such as increased hand washing, whenever your dog is sick.
Can dogs get bird flu?
While possible, the chances of a dog catching bird flu (avian influenza) are very low. However, there have been reported cases of bird flu in cats, dairy cows, poultry, and various wild animals. Dogs could potentially get exposed to avian influenza through contact with sick or dead birds, unpasteurized milk, or raw or undercooked meat (especially poultry).
Which dogs are at the highest risk for canine influenza?
Canine influenza virus can affect dogs of any breed, age, or sex, but dogs who have frequent exposure to other dogs are at the highest risk. Flu outbreaks have occurred in animal shelters, dog shows, kennels, dog parks, and dog daycares. Outbreaks can occur anywhere groups of dogs are in close quarters.
Very old dogs, very young dogs, immunocompromised dogs, and dogs with other underlying health conditions may be at a higher risk of becoming more seriously ill from contracting canine influenza.
Unlike human flu, dog flu does not seem to have a seasonal component. There is no defined “flu season” for dogs.
How is dog flu spread?
Dog flu spreads through respiratory droplets released when infected dogs sneeze, cough, bark, or breathe. It can also be transmitted by nose-to-nose contact with an infected dog or via fomites (contaminated surfaces or objects). Flu can survive on surfaces for up to 48 hours and on hands for up to 12 hours, but it’s fairly easy to kill with disinfectants.
Infected dogs generally start shedding the virus before they experience any symptoms. And they can continue to shed the virus for up to 10 days for H3N8 and up to 28 days for H3N2.
What are the symptoms of dog flu?
Canine influenza primarily affects the respiratory system. Signs of illness typically develop around 1-5 days after exposure and can last for weeks. Sometimes they are mild, but dogs can also develop more severe symptoms or pneumonia in dogs.
Symptoms of dog flu are similar to signs associated with kennel cough or other diseases that are part of the canine infectious respiratory disease complex (CIRDC). It may look like your dog has a cold.
Symptoms of dog flu include:
- Coughing: Many dogs with influenza will have a cough, although it is a common clinical sign for other respiratory conditions, as well as problems like congestive heart failure in dogs.
- High fever: While the body is fighting the infection, the dog may run a fever.
- Lethargy: It is common for your pup to be a lethargic dog due to not feeling well overall.
- Nasal discharge: Dogs with influenza may have clear to cloudy nasal discharge that can be thick or thin.
- Eye discharge: Watery or goopy eyes in dogs are also possible.
- Decreased appetite: When your dog is feeling sick and congested, he or she is less likely to want to eat.
The Journal of the American Veterinary Medical Association (JAVMA) published a study looking at dogs with respiratory illnesses who were being tested for influenza. It reported that for dogs who tested positive for H3N8 canine influenza, 98% were coughing or sneezing, 78% were lethargic, 78% had a poor appetite, and 76% had a fever.
This was in contrast to dogs who had a respiratory illness but tested negative for canine influenza. Their numbers were lower for each category: coughing or sneezing (84%), lethargy (46%), poor appetite (38%), and fever (36%).
Some dogs have no symptoms but can still shed the flu virus
Interestingly, not all dogs who contract influenza will be symptomatic. About 20% of infected dogs will show no signs. However, asymptomatic infected dogs are still contagious, so quarantining dogs with known exposure to the flu is important.
When should you make an appointment with the vet?
If your dog is lethargic, coughing and sneezing a lot, not eating, or breathing faster, it is a good idea to make an appointment with your vet. However, in the event that your dog is having trouble breathing or seems very sick, make an emergency vet visit rather than waiting for a regularly scheduled visit.
It is important to let the vet clinic know that your dog may have influenza. They will want to take special precautions to decrease the potential that your dog would spread the flu to other patients. This may involve measures such as having you use a different entrance, bringing your dog directly to a room, and having the veterinary team wear gowns and gloves.
How will the vet diagnose dog flu?
During the appointment, the vet will ask you questions about your dog’s symptoms, exposure to other dogs (especially dogs who are now sick), and travel to places experiencing an influenza outbreak. Then he or she will perform a physical exam.
Based on symptoms and the exam alone, it isn’t possible to definitively distinguish between the flu and other respiratory infections, so the vet will need to perform additional testing.
Flu tests for dogs
Your vet may recommend testing your dog for influenza (and possibly other viruses and bacteria, too). The most common test for influenza is PCR, which looks for genetic material of the influenza virus and can distinguish between the two strains. For the most accurate results, the vet will usually want to run the test within four days of your dog becoming sick. Since the vet typically sends the test out to a diagnostic lab, it may take a few days to get results.
Additional useful tests
In some situations, the vet may recommend a different test for flu. Additionally, the vet may run blood tests for dogs, such as a chemistry or complete blood count. This provides more information about the dog’s overall health status. If the vet suspects your dog might have pneumonia, he or she will probably suggest a chest X-ray to evaluate the lungs.
What is the treatment for canine influenza?
Treating canine influenza primarily involves providing supportive care while the virus runs its course. In most cases, dogs’ immune systems can get rid of the virus. Thus, the goal is primarily to ensure they get through it as comfortably as possible.
Treatment for dog flu may involve:
- Subcutaneous fluids for dogs with mild or moderate dehydration
- Hospitalization with intravenous (IV) fluids for more severe dehydration
- Nutritional support if the dog isn’t eating
- Nebulization for dogs with pneumonia
- Antibiotics for cases involving a secondary bacterial infection
- Anti-inflammatory medications
- Supplemental oxygen for cases of respiratory distress
- Cough suppressants for dogs who are coughing frequently
There is a wide range of severity for dogs who have the flu. Thus, the intensity of treatment varies with the severity of illness. Some dogs recover with little to no treatment, and others need more intensive care. Your vet will suggest a treatment plan after assessing your dog.
Can dogs take Tamiflu (oseltamivir)?
While Tamiflu® (oseltamivir) is a common treatment for influenza in humans, it is not approved for use in dogs, and off-label use for treatment of canine influenza is not recommended. Just like with antibiotics, we must judiciously utilize antiviral medications to minimize the development of resistance. Overuse of these drugs in animals increases the risk of resistant pathogens emerging and potentially infecting humans.
Aside from the risk of resistance, there is another barrier to using Tamiflu in dogs. Tamiflu is most effective if taken within 48 hours of the onset of symptoms. However, it is practically impossible to confirm a diagnosis of canine influenza within this time frame.
Pet parents may wait a bit to see if symptoms will resolve on their own before seeking veterinary care. Plus, canine influenza testing usually entails sending a sample to a diagnostic laboratory, so results aren’t immediately available. These factors mean most dogs are well past the 48-hour window for Tamiflu at the time of diagnosis.
What is the outlook for dogs with the flu?
Although highly contagious, canine influenza is rarely life-threatening, with a mortality rate of around 1 to 5%. This means that most dogs recover within two to three weeks and never look back. The good news, too, is that we can implement strategies to avoid exposure and vaccinate dogs at higher risk for infection.
Can dog flu be prevented?
There are two general strategies for preventing canine influenza: vaccination and avoiding at-risk environments.
Canine influenza vaccine
There are vaccinations available for both the H3N8 and H3N2 strains of canine influenza virus. Like the human flu vaccine, the goal is to decrease the chances of contracting influenza and the severity of the disease, but it may not prevent it entirely.
The American Animal Hospital Association (AAHA) does not consider canine influenza a core vaccine. This means they don’t necessarily recommend it for all dogs across the board. Instead, vaccination is based on individual risk assessment.
Dogs who are good candidates for the canine influenza vaccination are those with more exposure to other dogs or those who would be at a higher risk of complications:
- Dogs in animal shelters
- Show dogs
- Competitive athletes—agility, fly ball, etc.
- Dogs in kennels, boarding facilities, or dog daycare
- Dogs who frequent dog parks
- Dogs with compromised immune systems
- Brachycephalic (flat-faced) dogs or those with underlying heart or lung problems
Vaccine recommendations may vary geographically and/or over time. Canine influenza is not endemic (present all the time) in the US and does not present a constant risk. If there is an influenza outbreak locally, vets may recommend vaccination for dogs who would otherwise be considered low risk. Likewise, dogs with moderate exposure to others may not necessarily need a flu vaccine if there’s not currently an outbreak.
Your vet is your best resource for vaccine recommendations based on your own dog’s health and risk assessment. Also, your vet may contact you if there is a local outbreak of canine influenza so that you can take steps to decrease the risk that your dog will contract it.
Avoiding exposure to canine influenza
The best way to prevent illness is to avoid exposure to infected dogs or areas where they’ve recently been. Situations with lots of dogs in small areas are the highest risk for infectious disease transmission. During periods of known influenza outbreaks, avoid these places if possible. A stir-crazy dog is never fun, but it’s better than him or her catching influenza at doggy daycare or the dog park.
Isolating sick dogs and quarantining exposed dogs in a shelter or kennel setting
It is not always possible to keep dogs completely physically isolated from each other, such as in animal shelters. In these cases, vets recommend isolating dogs showing clinical signs of canine influenza and quarantining exposed dogs. The goal is to minimize the number of new dogs who are exposed and potentially infected.
What precautions should I take if my dog has influenza?
If your dog is the one with influenza or who was exposed to influenza, you should also take precautions to keep other dogs safe. It is best to keep your dog at least 20 feet away from other dogs (the distance respiratory droplets are thought to spread) for at least four weeks. This also means not taking your dog to the dog park, groomer, kennel, or anywhere other dogs may go. Wash your hands well after touching your dog, and don’t share any of his or her bowls, brushes, toys, etc. with other dogs.
If you have a separate room in your house where you can isolate your sick dog, that can be helpful in decreasing the spread to your other dogs. However, it is also possible that by the time you know your dog has influenza, he or she has shed enough of the virus that your other dogs are already exposed. Your vet can help you decide what is best for your dog’s situation.
Talk to your vet about canine influenza and dog flu shots
At your dog’s next vet visit, why not ask your vet whether he or she thinks your dog should receive a canine influenza vaccine? Together, you can make an informed decision about whether your dog’s lifestyle or health status means he or she could benefit from a “doggy flu shot.”
Remember, though, that avoiding environments where lots of dogs congregate during flu outbreaks is the other big piece of the prevention puzzle.
Has your dog contracted the flu?
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