What You Need To Know About Canine Influenza

STILL NEEDS EDITING

A dog flu epidemic has blown into the Windy City, sickening over a thousand dogs, and has been responsible for the death of at least five dogs since mid-March, according to Dr. Donna Alexander, administrator of Cook County Department of Animal and Rabies Control. Alexander concedes those numbers may be conservative and are likely growing, as some veterinary clinics continue to see as many as 50 or so new cases of confirmed or suspected canine influenza virus (CIV) weekly. And some emergency clinics are filled with sick dogs.

As of this writing, the outbreak is restricted to the Chicago metropolitan area. However, dogs do travel, of course. And dogs aren’t stopped at state lines. There have been several suspected, but yet to be confirmed, CIV cases in Missouri, Wisconsin, and Indiana.

“Of course, the canine influenza virus could easily spread to other cities, especially where there are dense canine populations,” says veterinary immunologist Dr. Cynda Crawford, clinical assistant professor of Maddie’s® Shelter Medicine Program at the University of Florida College of Veterinary Medicine – Gainesville. Crawford was among the first to identify the virus back in 2004 when a flu virus jumped species, as the equine influenza virus (horse flu) mutated into the canine influenza virus (dog flu) at a Florida racetrack.

While CIV outbreaks have occurred sporadically around the country, including in Chicago in 2008, the vast majority of dogs have never been previously exposed to this virus.

“There’s no built-in immune protection for most dogs,” says Dr. Brooke Bartell, who works in the ER at Chicago Veterinary Emergency & Specialty Center. “The result is that nearly all dogs exposed to the virus will get the virus.”

The tricky part is that all the dogs who get the virus don’t get sick. Crawford says about 20 to 25 percent infected with CIV present no signs of illness.

Dr. Natalie Marks in Chicago explains, “These dogs feel fine; they act fine, and have no symptoms – that’s good, except they are highly infectious and are particularly effective at spreading the virus because they continue their usual activities without anyone suspecting how contagious they are.”

And it so happens that the dog flu is highly contagious. Dogs easily spread it to other dogs. In fact, people can perpetuate the spread of the virus.

Marks adds “The virus can live on clothing for 24 hours or on objects for up to 48 hours.” As one example, if a dog carrying the virus kisses your hand or face (unless you wash your hand or face) even hours later, a healthy dog licking the same place can pick up the virus. Another example is a dog visiting a pet store that’s carrying the virus that licks a dog food package or a toy, followed even a day later by a healthy dog licking the same food package or toy will pick up the virus.

The good news is, relative to the number of dogs infected, most recover well. As mentioned, about a quarter of infected dogs don't get sick. And most of the dogs who do get sick suffer coughing, lethargy, a slight and lack of appetite. “Just like people who with the respiratory flu we get better on our own in three or four days without calling the doctor; many dogs recover without veterinary assistance.” Crawford says.

However, some dogs don’t get better or even worsen. About five to ten percent of dogs do need veterinary intervention, and some sick dogs require hospitalization. Sometimes their conditions deteriorate quickly into pneumonia. These seriously compromised dogs are surprisingly not puppies or elderly individuals in fragile health; they tend to be younger, active, healthy dogs.

All breeds are equally prone to CIV. Although, Bartell says she is always particularly worried about the ability of brachycephalic dog breeds (dogs with pushed in faces, such as the Pekingese, Pug, Bulldog or French Bulldog) to bounce back from any respiratory problem.

People and cats cannot get CIV.

In an effort to limit the continued spread of CIV, the Chicago Park District cooperated with the Chicago Veterinary Medical Association and posted signage to warn dog owners to enter dog friendly areas at their own risk. Some individual dog training classes are postponed, a handful of pet stores discourage visits from dogs and a small number of dog day cares shuttered their doors until the outbreak subsides.

“Limiting social contact keeps individual dogs safe, and also slows the virus circulation in the community,” Crawford says.

Of course, if more dogs were pre-emptively vaccinated for CIV, the epidemic may not have happened in the first place. “That’s true if we had about 70 percent of the dogs vaccinated, based on the human model for vaccination for flu,” says Crawford. “Certainly, with any significant number of dogs vaccinated not as many dogs would have been affected, which means it’s possible fewer would have died.”

Like the vaccine for the human flu, the vaccine for CIV may prevent infection, or may reduce severity of symptoms. Importantly, the dog flu vaccine (which requires a booster shot two to three weeks after the initial shot) also seems protective against pneumonia. And that’s important because when dogs succumb to CIV, pneumonia often plays a role, and certainly it's a cause for hospitalization.

“Many veterinarians think if we don’t see it, we don’t need to vaccinate,” says Dr. Derrick Landini in Chicago. “Boy, now most us wish we had been more proactive.”