When Chicago-area veterinarians started seeing more and more dogs coming into their clinics with coughs in February, they initially thought it was an outbreak of kennel cough.

However, it's now been confirmed that the virus that's sickened more than 1,300 dogs in Illinois, Indiana, Ohio and Wisconsin is a strain of dog flu never seen before in North America.

The highly contagious H3N2 strain is typically found in Asian countries and can also be spread to cats. While there is a canine flu vaccine, it has so far proven to be ineffective against the H3N2 strain.

"How it got there, I can't tell you," Dr. Amy Glaser, a senior research associate with New York State's veterinary lab, told the Chicago Tribune. "This caught us a little by surprise, and we didn't expect to find this virus in the United States."

Dogs infected with the virus often have symptoms similar to those humans with the flu exhibit, including coughing, sneezing, runny nose, loss of appetite and lethargy.

While this new flu strain is treatable, it can develop into pneumonia and be fatal in dogs with weak immune systems.

Six dogs have died of complications related to the virus in 2015.

To prevent the spread of disease, experts advise preventing dogs from having nose-to-nose contact. Before boarding your dog or taking him to doggy daycare, check with the facility to ensure there have been no cases of illness.

The virus is mainly concentrated in the Chicago area, and precautions are being taken to prevent further spread of the disease.

Dog parks have posted signs warning owners about the virus, and many doggy daycares are closing their doors or refusing to accept new dogs. Some vets are requiring dogs to wear masks, while others have asked pet owners to keep their dog in the car if the animal is coughing.

If your dog or cat exhibits flu symptoms, contact your veterinarian, and if you're exposed to a sick dog, wash your hands and clothes. Soap and water have proved to be effective at eliminating the virus.

The virus has an incubation period of about one to three days, and infected dogs should be kept isolated for at least 10 days after symptoms disappear.

If you live in the Midwest or if your canine is at increased risk — dogs recently adopted from shelters, dogs that frequent boarding facilities or dogs with weakened immune systems — talk to your vet about vaccination.

While the current vaccine may not be effective against the new flu strain, it will reduce the incidence and severity of dogs infected with the more common H3N8 strain.

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Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Dog flu spreads across Midwest, infects 1,300 dogs
The virulent strain has already killed 6 U.S. dogs, and experts say the current canine influenza vaccine has so far proved to be ineffective.