Thursday, 09/15/2022

The spread of the H3N2 virus among dogs has made its way into the public consciousness. The majority of dog owners are completely unprepared for this scare. For those who own a pet, it’s essential to understand how this virus spreads, why it’s so dangerous, and how you can protect your furry friend from contracting it.

The canine influenza virus (or CI virus for short) is a type of influenza virus that’s highly contagious among dogs. This blog examines everything you need to know about Canine Influenza Virus and its implications.

What is Canine Influenza?

Canine Influenza is a respiratory disease caused by the Influenza A virus. The symptoms of infection include fever, cough, lethargy, and excessive mucus production. Dogs with severe cases may have difficulty breathing and/or experience severe lung tissue damage. While the exact transmission path is unknown, it is believed to be spread through direct contact between animals and aerosolized respiratory secretions. 

Canine Influenza viruses belong to the family Orthomyxoviridae, a ‘Type A’ influenza virus. In the United States, two virus strains are prevalent: H3N8 and H3N2.

Canine Influenza is a viral infection spread from dog to dog through coughing and sneezing. When this happens, viruses latch onto the respiratory system of an infected animal and cause symptoms such as runny eyes, sneezing, and coughing. There are a large number of strains of the virus at any given time, which results in different outbreaks occurring every few years.

Canine Influenza can affect dogs of all ages and breeds but most commonly occurs in spring and fall. The ailment is a highly contagious disease that can lead to severe illness, especially in young, old, and immunocompromised dogs. If the pet is showing clinical signs of infection, ensure to get them to a vet as soon as possible. Also, ensure that no other dogs in your household or area show signs of infection.

How does Canine Influenza Spread?

Canine Influenza is spread through direct exposure to respiratory secretions (e.g., mucus, saliva, and vomit) from an infected dog. Humans should wash their hands frequently and avoid touching their mouths or nose while handling sick dogs.

The virus can be spread from certain types of birds, rodents, and pigs have been shown to carry the virus & pass it on to other animals. In addition, cats have been proven carriers of the organism and can spread the disease to dogs through direct contact with their wet noses or by sharing contaminated surfaces with them. 

The same goes for house pets. Dogs are capable of contracting the virus and passing it along to humans through close contact with them or through their urine, saliva, feces, or nasal secretions. 

Kennels, shelters, and daycare facilities are at increased risk of infection. It is crucial to clean and disinfect objects. If you have to interact with dogs in your community, such as at the dog park, ascertain to wash your hands with soap and water regularly and avoid touching your eyes.

 If you get close to an infected dog, avoid direct contact with your hands by wearing gloves and a face mask. If you need to work with dogs, wear a mask or other protective clothing to avoid cross-contamination.

Canine Influenza Virus Viability 

Surfaces48 hours
Clothing24 hours
On hands12 hours

Note: The virus has an incubation period of 1 to 5 days. In certain cases, clinical signs appear 2 to 3 days after exposure. Dogs infected with H3N2 often show respiratory signs between 2 and 8 days after infection. Some canines may show no signs of illness but have a subclinical infection and shed the virus.

What are the Symptoms of Dog Influenza?

  • Lethargy: Lethargy might be the most obvious sign that your dog has canine Influenza. Dogs can become lethargic due to many factors, but when it is due to canine Influenza, it is usually a serious condition. Lethargy can happen suddenly or gradually, although sudden lethargy is often a sign of severe infection. Lethargy is also common, and many other illnesses can also cause it.
  • Coughing: Coughing in dogs is another common sign of canine Influenza, especially at the onset of the illness. As the infection progresses, coughing can become less frequent or persistent. 

If your dog is coughing and producing a lot of mucus, it’s essential to bring that coughing to a vet’s attention as soon as possible. Coughing that does not seem to get better with antibiotics shouldn’t be ignored. 

  •  Difficulty breathing: Dogs that have severe canine Influenza can struggle to breathe. At the onset of the illness, these dogs might have labored breathing “dyspnea ” and can appear to be choking. They might also experience wheezing, or a “wheezy” sound when breathing, or they might hold in pain when breathing deeply.
  •  Severe lung tissue damage: If your dog is showing signs of severe infection, there is a chance that their lung tissue might be damaged and that they might need to be intubated (put in a breathing tube). If this happens, your dog will most likely need to be hospitalized and put on IV fluids and antibiotics to treat the infection.

Other sign includes:

  • Nasal discharge
  • Sneezing
  • Ocular discharge
  • Anorexia,
  • Conjunctivitis
  • Fever
  • Diarrhea and/or vomiting


Here are the details for Canine Influenza symptoms with this infographic:

How Do You Treat Canine Influenza?

If you suspect that the pet has canine Influenza, contact your veterinarian or animal hospital for testing and treatment recommendations. If your canine tests positive for the disease, keep them away from other dogs until they completely recover. You can also try disinfecting your home with an antibacterial spray or wipes.

Most pets recover from canine Influenza within 2-3 weeks. However, Secondary bacterial infections such as Pneumonia, dehydration, or other health factors such as pregnancy, pre-existing pulmonary disease, tracheal collapse, etc. may necessitate additional diagnostics and treatments including, but not limited to:

  • Antimicrobials for suspected secondary bacterial infections.
  • Nonsteroidal anti-inflammatory medications.
  • Fluids to correct dehydration or maintain hydration.

Treatment modifications should be made as required, based on response to treatment. To prevent virus transmission, the household should be isolated for a minimum of four weeks.

How to Prevent Canine Influenza? 

The best way to prevent canine Influenza in your dog is through vaccination. If your dog is already showing signs of infection, it’s important that you get them to the vet as soon as possible.

Vaccinating your dog will help protect them from getting the disease and will also help protect other dogs in your community that might be susceptible to the disease.

  • Clean your dog’s environment: A clean house, yard, and car protect you from contracting many diseases. Clean your house regularly, and do not allow your dog to run around in the dirt or in a field. Make sure that your dog’s environment is clean and disinfected regularly. 
  • Wash your hands regularly: Hands are the main entry point for viruses and bacteria – keep them clean by using soap and running them under a clean water stream regularly. 
  •  Make sure that your dog is healthy: If your dog is showing any signs of illness, such as coughing, lethargy, or difficulty breathing, take them to the vet as soon as possible. A healthy dog is less likely to develop an infection than an unhealthy one.

How is Canine Influenza Diagnosed?

Canine Influenza cannot be solely diagnosed by clinical signs. Tests are specific tests available to diagnose and identify strains of canine influenza virus. Tests include:

  • Virus isolation.
  • Immunoassays to detect virus antigens.
  • PCR to detect virus nucleic acid.
  • Serology for antibodies specific to the virus.

PCR may be considered the most reliable test for the diagnosis of canine Influenza. 


Many layers to this topic cannot be covered adequately within these few paragraphs, and there is much more information compared to what is written here. However, understanding some key concepts can help you plan ahead and handle the situation if it should ever arise so that you don’t put your dog at risk unnecessarily and so that everyone else around you is not exposed unnecessarily as well.

It’s important to understand the signs of infection and how they are transmitted. It’s also crucial to be prepared for any outbreak, as it could happen anytime. With a bit of preparation, you can be ready to take care of your dog if there is an outbreak. 

Fortunately, H3N2 is only present in dogs. Because of this, dogs are the only ones that can be infected. Maintaining cleanliness and disinfection of your environment and your dog is important. Additionally, make sure to follow the vaccination guidelines. If your dog is vaccinated against the canine influenza virus, it will be protected from spreading the infection to others.

Disclaimer: The content on the site is for educational purposes only, and it does not provide medical advice. The shared information must not be treated as a substitute for or alternative for medical practitioner advice, diagnosis, or treatment. Regarding any concerns about your pet’s health, seeking veterinary guidance is of utmost necessity. Each pet has specific health, fitness & nutrition needs. Do not disregard, avoid or delay pet health-related advice from veterinarians based on reading the information provided on this site.


  1. What is the duration of canine Influenza?

The duration of canine Influenza varies between dogs but generally lasts for 3 to 7 days. Symptoms typically include increased thirst, increased frequency of urination, and general ill mood. Fever may also occur, and this typically peaks at around day 4 or 5. 

Towards the end of the infection, dogs may experience vomiting and/or diarrhea. The illness can be severe and fatal in some cases. Dogs may be contagious for 2 to 8 weeks before they develop signs of the disease.

  1. Is canine Influenza highly contagious?

The answer to this question is going to be very individual and could vary from one dog to another. Some canines may be more susceptible to the disease than others and may be more likely to pass it on to other dogs. In general, the answer is going to be yes; canine Influenza is highly contagious. 

Although it’s not as contagious as canine flu, it is still effortless for the virus to spread between dogs. The most common way it will spread is through direct contact or contact with infected dogs’ excreta, which can be contaminated with their shed nasal secretions or urine, which may contain virus particles.

  1. What is the difference between kennel cough and canine Influenza?

Kennel cough is a prevalent infection in dogs that affects the respiratory tract. It is caused by a bacteria known as Bordetella bronchiseptica. Canine Influenza is a viral disease caused by the H3N2 and H3N8 virus strain.

Canine Influenza, or “dog flu,” is a more serious infection in dogs with similar symptoms to kennel cough, which may include lethargy, high fever, lack of appetite, vomiting, coughing, sneezing, and nasal discharge. The symptoms of ‘Dog Flu’ are more severe compared to kennel cough signs. The biggest difference between the two infections is that kennel cough is treatable with antibiotics, and Dog Flu is not. Canine Influenza is also highly contagious, requiring more aggressive treatment than Kennel Cough.  

  1. Can you test a dog for Influenza?

The reliable way to diagnose canine influenza virus infections is by serological tests. PCR tests are also helpful in directly detecting the virus through nasal swabs or respiratory tissue. 

  1. How often do dogs need a canine influenza vaccine?

Get your dog a flu shot yearly. To be fully vaccinated against Influenza, ensure that your pet receives two initial sets of vaccinations followed by a yearly booster.



Alex Schechter

About Alex Schechter About Alex Schechter