A dog flu has hit the United States.

The big question is how far will it spread.

Pet owners in Florida are being urged to vaccinate their dogs against canine influenza after more than a dozen dogs in that state tested positive for the virus.

Officials at the University of Florida Veterinary College of Medicine confirmed 12 dogs tested positive to the H3N2 strain of the influenza.

It is suspected these animals contracted “dog flu” after attending dog shows in Perry, Georgia, or Deland, Florida, or coming into contact with dogs that attended those shows.

“It is very important for both veterinarians and dog owners in the state of Florida to have a very heightened awareness of the presence of this virus in the state … It may be coming to their local community, which will then increase the risk for exposure of dogs in that community.” Dr. Cynda Crawford, DVM, the Maddie’s clinical assistant professor of Shelter Medicine at the veterinary college, said at a press conference.

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Details on the dog flu

According to the Centers for Disease Control and Prevention (CDC), symptoms of dog flu include a cough, runny nose, and fever.

While the virus is highly contagious, some dogs will not show symptoms of the illness.

The H3N2 strain present in Florida is the same strain that resulted in a severe outbreak of canine influenza in Chicago in 2015. It originated as an avian flu that adapted to infect dogs.

Colin Parrish, PhD, is a professor of virology at the Cornell University College of Veterinary Medicine. He studies the emergence and spread of canine influenza viruses.

He said the H3N2 strain was brought to the United States from Asia.

“The virus originated in China most likely in late 2005 or early 2006. From there it spread to Korea and to Thailand in the next few years. It was introduced into the USA from Korea in 2015, most likely through the importation of rescued dogs from Korea,” he told Healthline.

The canine H3N2 virus differs from the human H3N2 virus.

Parrish said that in humans the H3N2 virus has potential to reach pandemic levels, but the risk is lower in dogs due to their social habits.

“The rate of transfer in dogs is less efficient than in humans, probably due to their lower contact rates among dogs ... For example, dogs don't go to work or school or take as many international flights, or engage in other activities that allow transfer of viruses between humans,” he said.

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The risk of the flu spreading

Crawford advises that those involved in the show dog circuit to exercise caution.

“It is a high risk to take dogs to dog shows at this time because there could be dogs in attendance that are infected and contagious to other dogs … There is substantial risk,” she said.

The virus can spread among dogs in kennels or shelters. Dogs that are less likely to have exposure to other dogs in such environments have a lower risk of infection.

“The dogs that stay within the confines of their own home, their yard, and walk around the block are the lowest risk group likely for encountering this virus,” Crawford said.

According to the CDC, there is currently no evidence of transmission of a canine influenza virus from a dog to a human.

However, a fact sheet on the CDC website notes that “influenza viruses are constantly changing and it is possible for a virus to change so that it could infect humans and spread easily between humans.”

The CDC says infection of humans with new influenza viruses are concerning and could pose a pandemic threat.

“For this reason, CDC and its partners are monitoring the canine influenza H3N8 and H3N2 viruses (as well as other animal influenza viruses) closely,” the fact sheet states.

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Vaccine available

There is a vaccine for the canine influenza virus, including the strain currently present in Florida.

Zoetis and Merck Animal Health, producers of the vaccine, said they have anticipated an additional demand and are increasing supplies.

Crawford said it’s not too late for dog owners in Florida to talk with their veterinarians about vaccinating their dogs.

“Now is the time for veterinarians and dog owners to really consider getting their dogs vaccinated as soon as possible to provide protection against infection by this virus or the disease the virus causes,” Crawford said.