But in 2004, researchers looking at unexplained deaths of greyhounds at dog racing tracks discovered a new influenza virus that can infect dogs. Since then, the virus has been found in 30 states and Washington D.C., said Cynda Crawford, an assistant professor of shelter medicine at the University of Florida, who first found the flu virus. Now it's another thing dog owners need to be aware of, she said.
WebMD went to the experts to get answers to some of the biggest questions about dog flu.
1. What are the symptoms of dog flu?
Diagnosing dog flu can be difficult, Crawford said. That's because dog flu symptoms - a low fever, persistent cough, runny nose, and just feeling blah - are the same as some other common respiratory diseases. A test is needed to confirm the diagnosis.
2. Can people catch the flu from their dog, and vice versa?
Although people and dogs can catch influenza viruses, they are susceptible to different strains of the virus, Crawford said.
For that reason, people don't need to worry about catching the flu from their dog, said Rubin Donis, PhD, chief of the molecular virology and vaccines branch at the CDC.
"We're obviously keeping an eye on that, but so far we haven't seen any evidence that people can contract the virus from their pets," Donis said.
There has been some evidence that dogs might be able to catch the flu from people, Donis said. But there's not enough data on the subject.
3. How serious is dog flu?
If your pet gets the flu, don't panic. The virus isn't highly dangerous, said Edward Dubovi, PhD, director of the virology laboratory at Cornell University's College of Veterinary Medicine and the person who first isolated the canine influenza virus from a sample sent to him by Crawford.
But just as with people, dog flu can lead to secondary infections that could develop into life-threatening pneumonia.
"The secondary bacterial infections are where the real danger lies," Dubovi said. "But most dogs, with the proper veterinary care, aren't impacted severely."
Experts estimate the fatality rate at 1 percent to 5 percent. Crawford said the real problem is that because dogs haven't been previously exposed to the virus, they have no immunity. So nearly 100 percent of dogs exposed to dog flu catch it, and 80 percent will show symptoms within four days, she said.
4. How likely is my dog to catch dog flu?
High-risk areas for catching dog flu include boarding kennels, shelters, doggie daycares and dog parks. People who attend dog shows also have been on high alert for the virus. Joy Dillon of Nashville, Tenn., who breeds and shows Chihuahuas, says that people in the dog show circuit are vigilant about keeping sick animals out of shows.
"We're concerned, but we take precautions, and we have a great grapevine," Dillon said. "If someone's dog got sick at a show, everybody at that show would know before the next show."
Where you live also can have an impact. Crawford said that some areas, such as the east coast from Virginia to Connecticut, as well as southern Florida, the Denver area, and some parts of Texas, have had widespread outbreaks, and other areas have had none.
"We also find it's more prevalent in major metro areas, but that's probably because there are higher concentrations of dogs in those areas," she said.
Crawford said they haven't found any patterns showing dogs of certain ages or breeds to be more susceptible to the virus.
"Some dogs, like flat-faced dogs, are more at risk if they develop pneumonia, because they already have obstructed breathing passages, but they aren't more at risk of contracting the influenza virus," Crawford said.
Researchers also haven't found a seasonal element to the disease. So instead of cases increasing during the fall and winter, it seems to occur year-round.
5. How is dog flu treated?
Treatment for dog flu is very similar to that for people. Because antibiotics don't work on a virus, the usual advice is lots of rest and fluids. But antibiotics could be prescribed for secondary infections, Dubovi said.
6. Should my dog get the dog flu vaccine?
A dog flu vaccine, approved in the spring of 2009, is now available at veterinary offices. Dubovi said the vaccine won't prevent a dog from getting the virus, but it will lessen the severity and the duration of the disease. Whether or not to vaccinate is a personal choice, he said.
"If I lived in New York City and I was getting ready to board my pet for the holidays, I'd definitely get the vaccine," Dubovi said. "But if I lived in Minneapolis, where there's never been a diagnosed case, I probably wouldn't use it."
Crawford said the vaccine consists of two shots, given three weeks apart. The shots contain the killed virus and help dogs build immunity to it. She said so far dogs don't seem to have adverse reactions to the vaccine.
For most dogs, the flu is little more than an inconvenience, Crawford said.
"People really don't need to be freaked out about it. The public just needs to be aware that dogs can get the flu, too," Crawford said. "But it's very much like the flu people get. People just need to talk to their vet about their risk and whether their pet needs a vaccination."
7. Can dogs get swine flu?
Dubovi said there's no evidence that dogs get swine flu, or the H1N1 virus. But some dogs have contracted avian flu, and some cases have been fatal, he said.
By Sandy Eckstein
Reviewed by Mark Stickney
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