A newly discovered virus has killed dogs in at least seven states, and veterinarians, kennel operators and pet owners are concerned because researchers say there is no vaccine and dogs do not have immunity to the new flu.
Dr. Cynda Crawford, an immunologist at the University of Florida's College of Veterinary Medicine, said in an audio interview posted on the university Web site that the disease is only deadly in rare cases -- about 10 percent in puppies and old dogs -- but is of concern because it is spreading rapidly.
It is believed that the new virus may have mutated from an equine influenza strain, she said.
Like most flu viruses, it can be spread by air, as well as by contact, and the populations of dogs most at risk are those in shelters, kennels, boarding operations or other situations where a lot of dogs are housed under one roof, she said.
The disease could also spread in parks where pet owners let their dogs off the leash to socialize, vets say. Dog parks are a perfect playground for contagious diseases because when animals share toys and water dishes, they also are sharing germs.
The symptoms of the disease include coughing and sneezing, and there is concern that it could be spread in vet waiting rooms, Crawford said.
"When you bring a bunch of dogs together under one roof, if a dog happens to be infected, then the virus will spread rapidly," she said. She compared the situation to what happens with young children in school.
As yet, there is no test for the flu that vets can administer, she said.
The virus is too new for any dogs to have developed immunity to it, so pet owners should watch their dogs carefully for any symptoms.
"The concern is that the dog population on the North American continent is wholly 100 percent susceptible," Crawford said.
Seattle veterinarian Dr. Kenneth McKim recently treated some dogs with "kennel cough," but said the new virus is different.
"It's a more severe disease (with) high fever," McKim said. "It's got more complications with pneumonia and congestion."
There have been outbreaks of this new dog flu in kennels, race tracks and shelters along the East Coast. But not on the West Coast, yet.
"It's something that we're going to be watching for in the Northwest," McKim said. "There have been no reported cases of it here yet, but I think it's something that veterinarians are going to be on the watch for."
The majority of the deaths have occurred at greyhound tracks in Florida, Massachusetts, Arizona, West Virginia, Wisconsin, Texas and Iowa, but there have been documented cases in some kennels and shelters.
Vets stress that the flu is no reason for pet owners to panic, but they should take some precautions. If you take your dog to a dog park, bring the dog's own water dish and toys, they say.
If you kennel your dogs, or take them to a doggie day care, vets say you should make sure the facility is clean, well-ventilated and requires all dogs to be current on their shots.
ABC News affiliate KOMO-TV in Seattle contributed to this report.