Pet owners are worried about a dangerous strain of dog flu spreading through western states.
Health officials in the Seattle area say tests confirmed this week that the virus was found in dogs who stayed at a local kennel and doggie daycare facility. The kennel owner reported that 80 to 90 dogs there developed respiratory illness since December.
The highly contagious illness, also called canine influenza, appears to have begun spreading last spring in the Chicago area and sickened more than 1,000 dogs in the Midwest. Although most dogs recover, a handful of deaths were reported. It has since spread to about 25 states.
"It kind of stunned most of us in the veterinary community because it spread like wildfire," veterinarian Dr. Ernie Ward told CBS News when the first wave of the outbreak was raging last April.
Experts say this strain of the virus, called H3N2, was first seen in Asia but only recently appeared in the U.S., meaning dogs in this country are highly vulnerable. "None of the dogs have immunity to fight it off, so you see large numbers of dogs getting ill when the virus starts to circulate," Dr. Beth Lipton, veterinarian for Public Health Seattle and King County, told CBS News.
Click through to learn more about the symptoms, how it spreads, and what you can do to help keep your pets healthy.
The most common symptoms of dog flu are high fever, cough, runny nose, watery eyes, sore throat and loss of appetite. Dogs who catch it usually feel lousy for about two weeks.
Steve Gilberg, a digital marketer in Chicago, said his 6-year-old pug-Chihuahua mix, Joey, got an especially bad cough last spring. "He just started coughing really, really hard, kind of like a smoker's hacking cough, coming from the belly," Gilberg said.
How can you tell if your dog may be coming down with it?
Dr. Brian Collins, a companion animal veterinarian at the Cornell University College of Veterinary Medicine in Ithaca, New York, urges owners to pay attention to changes in behavior, such as dwindling interest in eating, drinking and playing, labored or rapid breathing, or lethargy.
"If he's always happy to eat and now he isn't, that isn't a good sign. Are they clingy when they are usually close, removed when they are usually just a bit aloof?" said Collins.
How it spreads
Health officials say dog flu spreads the same way human flu does: through virus droplets in the air from a sneeze or cough, or by touching contaminated objects or surfaces. The virus can live in the environment for about two days and can linger on hands or clothing for up to 24 hours.
Dogs may be especially likely to catch it if they spend time in places where lots of dogs congregate, such as dog parks, pet day care, pet grooming or boarding facilities, or veterinary clinics.
"If they're in a boarding and day care situation, make sure they're up-to-date on vaccines," advises Dr. Grace Anne Mengel, Penn Vet staff veterinarian.
Lipton, the Seattle public health vet, says some dogs don't show any symptoms at all, but are able to infect others. "This strain of canine influenza isn't particularly deadly, but can cause a secondary infection like pneumonia, which can kill dogs," she said on the agency's blog.
Experts say humans cannot catch dog flu.
Helping a sick pet
If your dog seems sick, start by taking its temperature. You can't just feel a dog's forehead to see if it's running a fever, Collins said. Use a digital thermometer to take readings under an armpit or in the most accurate area - the backside.
Food and fluids are important, so keep trying to entice your dog to eat and drink. With a pet that isn't eating well, offer fare that's a bit more tempting, but be careful it doesn't cause a stomachache. Try some baby food, canned meals or dry food softened with water.
Dogs probably have achy muscles, a sore throat and stuffy head while feeling tired and run down, so let them lie around and sleep more than usual, as long as they are still getting up to go outside and staying hydrated.
Do drugs help?
There was no vaccine for the H3N2 strain when it started spreading through the Midwest last spring, but Merck Animal Health says it has recently been granted a conditional license for Canine Influenza Vaccine H3N2.
If your dog is already sick, a vaccine won't help, said Dr. Drew Sullivan of the Medical District Veterinary Clinic at Illinois in Chicago. "We can't treat the virus, just the symptoms."
Antibiotics might be prescribed if a flu-infected dog contracts pneumonia, a complication which can be life-threatening.
Doctors warn against treating dogs with cough syrup or other over-the-counter medicines.
Avoiding dog germs
Infected dogs can be contagious for two weeks, so keep pets -- sick or healthy -- away from close contact with other animals. Flu can run rampant through doggie day care centers and kennels where many pets are kept in close quarters.
"Because it's so contagious, if boarding facilities, shelters, and doggie day cares experience an outbreak they may need to temporarily close, which would be highly disruptive," said Dr. Beth Lipton, the Seattle and King County public health vet.
"Don't stop going out with your dog. It's important for dogs and people to socialize," said Penn Vet's Dr. Grace Anne Mengel. "Dogs need exercise and fresh air. But try to avoid your dog having nose contact."
The outbreak last year in the Chicago area hit at the height of spring break season, when many families had reserved kennel space for their dogs. Boarded dogs caught flu from other dogs, adding to the outbreak, said Dr. Ken Goldrick, a veterinarian at Family Pet Animal Hospital in Chicago.
"We saw many families that week after Easter," Goldrick said. "They'd say, 'We boarded him for the weekend while we went to visit family, and now he's coughing.'"
Dr. Ernie Ward offered some advice for families that need to use these services. "If you have to take your pet to a doggie day care, a shelter, even a veterinary clinic, find out what they're doing to help mitigate the spread of this," he said. "What kind of protocols do they have in place for cleaning? Do they have protective gear? In our veterinary hospital, when we are seeing a high fever, coughing, nasal discharge case, we go into lockdown. I mean, this is something people need to take seriously because it is so contagious."
Are other animals at risk?
Lipton says that in Asia, where the H3N2 strain of canine influenza was first detected, it has been reported to infect cats. But in the U.S., cases of cats developing dog flu are extremely rare. She adds that there is "some evidence" that pet guinea pigs and ferrets could also become infected.