DOG (CANINE) INFLUENZA HAS CAUSED PERIODIC OUTBREAKS of infection in the United States since 2015. While the virus can rapidly spread through kennels, shelters, and daycare facilities, most dogs will recover spontaneously. Today we explore the question: Do dogs get the flu?
Today we explore canine influenza, also known as dog flu. This contagious respiratory illness is caused by certain Type A influenza viruses known as “canine influenza viruses.” The illness does not transfer to humans.
I also want to briefly discuss the canine flu history, the level of seriousness of the infection, testing, and management.
“A person can learn a lot from a dog, even a loopy one like ours. Marley taught me about living each day with unbridled exuberance and joy, about seizing the moment and following your heart. He taught me to appreciate the simple things-a walk in the woods, a fresh snowfall, a nap in a shaft of winter sunlight. And as he grew old and achy, he taught me about optimism in the face of adversity. Mostly, he taught me about friendship and selflessness and, above all else, unwavering loyalty.”
― John Grogan, Marley and Me: Life and Love With the World’s Worst Dog
What is canine influenza (dog flu)?
There are two strains of canine influenza, including H3N8 and H3N2. H3N8 viruses originated in horses, spread to dogs, and now spread between dogs. While scientists have been aware of the H3N9 equine influenza (horse flu) virus for over 40 years, cases emerged among greyhounds in 2004.
In 2005, experts designated this dog flu virus as a “newly emerging pathogen in the dog population” in the United States. It has now been detected in dogs across much of the United States.
The other strain of canine influenza is H3N2, a virus that originated in birds and spread to dogs. The virus can also spread from dogs to cats. Scientists discovered canine influenza A H3N2 in South Korean dogs in 2007. Researchers first detected it in the United States in April 2015.
“What do dogs do on their day off?; Can’t lie around — that’s their job!”
― George Carlin
How dangerous is canine influenza?
Fortunately, the vast majority of healthy dogs survive the infection. The discoverer of the disease, Dr. Cynda Crawford of the University of Florida (USA), estimates that approximately two to five percent of infected canines will die from the infection; similar to the human flu virus, it threatens few healthy individuals. The onset of pneumonia characterizes severe illness.
Experts said that canine influenza could spread easily in shelters, kennels, and daycare facilities, but most dogs will recover.
What about humans? The H3N8 and H3N2, canine influenza virus strains differ from seasonal influenza A(H3N2) viruses that spread annually in people. Fortunately, the canine variety does not spread to us.
But the story is more complex. First, the canine influenza virus (CIV) is a highly contagious viral infection affecting dogs and cats. And a 2018 study suggests that humans may someday be at risk. Domestic dogs have flu viruses that have the potential to jump to humans. Researchers found these potential virus-transmitting dogs in China.
We have seen this play out before. For example, the 1918 Spanish Flu pandemic that killed 50 to 100 million people started in birds. And the 2009 Swine Flu pandemic was transmitted to humans from pigs, killing an estimated 203,0000 people worldwide. Adolfo Garcia-Sastre, Ph.D., director of the Global Health and Emerging Pathogens Institute at the Icahn School of Medicine (New York City), reminds us of this:
“The majority of pandemics have been associated with pigs as an intermediate host between avian viruses and human hosts. In [our] study, we identified influenza viruses jumping from pigs into dogs. We now have H1N1, H3N2, and H3N8 in dogs. They are starting to interact with each other.”
But Garcia-Sastre offers that we can rest easy for now: “At this moment, there is no reason to be alarmed, as the chances of dog-to-human transmission are very [low].”
Canine influenza — Symptoms and management
Canine influenza symptoms are similar to the human flu: cough, runny nose, and fever. One sign that dog flu is present is a cough that does not respond to antibiotic or cough suppressant therapy and lasts 10 to 21 days.
This cough may be productive or non-productive (dry). The dog may be lazy or have a diminished appetite. Flu virus H3N2 strains appear to be associated with more severe illness signs. The canine influenza virus may be confused with other respiratory infections, including kennel cough. A skilled veterinarian can determine the diagnosis.
Dogs with cardiorespiratory conditions have a high risk for the canine influenza virus, as do older dogs. In addition, canines with short and flat faces are at higher risk. Such breeds include
- Boston Terriers
- Boxers
- Pekingese
- Pugs
- Shih Tzus
Canine influenza virus — Management
Given the viral nature of the condition, the canine influenza virus is managed primarily with supportive care. The dog should be in a warm and dry area, away from other dogs. Hydration and a quality diet can help, too.
Some affected dogs with mild dog flu develop a secondary bacterial upper respiratory infection. Symptoms include a thick green mucous discharge from the nose. Broad-spectrum antibiotics can be helpful.
Some dogs with pneumonia need intravenous fluids, potent antibiotics, and hospitalization. Fortunately, most recover within two or three weeks. Exposed dogs should be isolated for four weeks to prevent the further spread of the disease.
The canine influenza virus is highly transmissible, spreading through respiratory secretions — coughing, sneezing, and nasal discharge). Contamination of kennel walls and floors, food and water bowls, collars and leashes, and the skin and clothing of those coming in contact with an infected dog are all potential transmission vectors.
Dog flu has no high season; the infections occur throughout the year. Finally, vaccines protect dogs against the H3N2 and H3N8 variants of the canine influenza virus. Your veterinarian can give you information about vaccination.
Thank you for joining me for my piece “Dogs get the flu?” I hope that you have a joy-filled day.
