As if we didn’t already have enough flu to deal with this year, there's another new strain that's taking its toll on man's best friend.

It's called H3N8 flu, and it's been around for decades -- and it doesn't affect humans. But it recently jumped from one species to another, and now it's affecting dogs everywhere.

“In this case, it was originally an equine influenza, which we’ve known about for 40 years,” Dr. David Bessler, senior emergency clinician at NYC Veterinary Specialists and 24-Hour Emergency in Manhattan told FoxNews.com.

“In 2004 there was a couple of outbreaks in greyhound colonies in racetracks down in Florida of upper respiratory disease, and from that we eventually found out it was canine influenza.”

In September of 2005, the virus was identified by experts as “a newly emerging pathogen in the dog population,” the Centers for Disease Control and Prevention said on its Web Site.

“This disease is incredibly contagious,” Bessler said. “Virtually every dog exposed to the virus will become infected. It’s that contagious.”

Dogs at highest risk are often involved in "social" situations such as doggy daycare, dog shows and dog parks. The canine flu is spread by direct contact with respiratory secretions from infected dogs, so pet owners whose dogs are showing signs of infection should avoid social interaction with other dogs until the symptoms have passed.

Full Coverage H1N1: Click here

RELATED: LiveShots Blog

The problem with H3N8 flu is that mimics another syndrome that affects dogs.

“The symptoms are virtually indistinguishable from a bunch of other respiratory diseases in dogs that we’ve grouped together under the name 'kennel cough,'” Bessler said.

“There’s really no way to tell, based on symptoms alone, that you’re dealing with canine influenza rather than any of the other causes of kennel cough, but there are tests that are available.”

You can also look for signs of the flu in your dog, which include:

— Cough (sounds like the dog has something stuck in its throat);

— Runny nose;

— Discharge from the eyes;

— Fever (hot ears are often a sign of fever);

— Loss of appetite;

— Weakness and lethargy.

If you see these signs, you should take your dog to the veterinarian right away, so they can test for the flu.

“The most important thing to remember is a vast of majority of these cases are mild and resolve on their own even without any treatment,” Bessler said. “A minority of cases can progress to more serious diseases such as pneumonia, and a very, very small minority will result in death. There’s about a 5 percent mortality rate.”

So what can you do to protect Fido? The same thing you do for yourself and your children: get your pooch a flu shot.

“It’s called the canine influenza vaccine and it’s been granted a provisional license by the USDA, which is usually reserved for cases of extreme need to prevent animal suffering and/or economic loss. Basically for an emergency situation,” Bessler said.

VOTE: Would you get your dog vaccinated?

The vaccine, manufactured by Schering Plough, doesn’t protect dogs from becoming infected, but it lessens symptoms and shortens how long a dog is contagious.

“And so by shortening the time a dog is contagious, the vaccine also helps prevent the spread of the disease,” Bessler added. “It’s also a safe vaccine. There was a field test where more than 700 dogs were vaccinated and there were no reported side effects or adverse reactions.”

If your dog does come down with the flu, there are several courses of treatment, including antibiotics and intravenous fluids to keep your pooch hydrated.

And unlike H1N1, Bessler said, humans don’t have to worry about being affected by H3N8.

“To date there have been no cases of transmission to humans,” he said.

Still, the CDC is keeping a close eye on H3N8, as well as other animal flu viruses, because influenza viruses are constantly changing and there's always a chance that they may jump species.

Click here to read more about canine influenza from the CDC.