Canine influenza is suspected of infecting nearly 300 dogs in Minnesota since April, when the outbreak of the highly contagious virus was first reported. It's the largest canine disease outbreak in decades.

"For dog disease in Minnesota, it's the biggest news for the past 40 years at least," said Graham Brayshaw, director of veterinarian medicine at the Animal Humane Society.

That's why the state Board of Animal Health this month encouraged dog owners to talk to their vets about the canine influenza vaccine to protect their pups and stop the spread.

But there's still a widespread shortage of shots in the state and nationwide, though supply has increased. Last week, a canine influenza vaccine clinic at the Animal Humane Society sold out immediately.

The St. Paul Pet Hospital's canine flu vaccine supply sold out as soon as appointments were announced. Veterinarian Abigail Maynard said it's pretty difficult for clinics to get supplies of the vaccine since only one company makes it and the demand is high.

The outbreak began in Minnesota when the Humane Society reported that a dog transported from Oklahoma had infected all of its 200 dogs. The nonprofit shut down its three shelters in Golden Valley, Woodbury and Coon Rapids and paused all pet adoptions until May, making it the Humane Society's longest closure due to an animal-related outbreak.

Since then, Brayshaw said, the Humane Society has had zero cases of canine flu, which causes similar symptoms to the flu in humans, and has implemented stricter protocols, testing and isolating any dog with respiratory symptoms for seven days.

"We've doubled down the best we can to make sure we're not importing anything that's contagious," he said.

Of the nearly 300 suspected canine flu cases in Minnesota, 95 are confirmed infections and most of them are in Hennepin County, according to the state Board of Animal Health. It's likely there are many more infected dogs who haven't been tested or visited a veterinarian to confirm the disease.

The number of infections is still low, given that there's an estimated half-million dogs in the metro area. Minnesota is reporting far fewer cases of canine influenza than other states, including Texas and Oklahoma.

"It's at least not exploding in numbers," Brayshaw said.

It takes six to eight weeks for the vaccine to be fully effective. Since most dogs stay at the Humane Society's shelters for an average of a few weeks, the nonprofit is focusing its supply of 1,000 vaccine shots on dogs in the community that go to its clinics, Brayshaw said.

He encouraged people who take their dogs to boarding facilities, doggy day care or dog parks to consider vaccinating their pups. "This is a disease I would worry about, based on the social activity of my dog," he said.

Canine flu is more serious than kennel cough, a respiratory disease that's akin to a mild cold. Puppies, senior dogs and those with weakened immune systems are more susceptible to complications. Vaccinating those dogs can help reduce the severity of the illness, according to the Board of Animal Health.

As with humans and COVID-19, all pups play a role in slowing the spread of the disease, said Holly Rudolf, a Mankato veterinarian who owns Halo Pet Care.

"The community helping to practice avoidance, vaccinating and using good hygiene practices is going to be helpful in keeping our pet population in the state protected," she said.

At the University of Minnesota's Veterinary Medical Center, some dogs with canine influenza had to be hospitalized to receive oxygen. But most dogs have mild cases and recover quickly, said Lindsay Merkel, a veterinarian and associate professor. Canine flu has a low mortality rate; according to the Board of Animal Health, two dogs have been euthanized due to complications from the disease.

Canine influenza will likely continue to spread before the virus eventually dies out, Merkel said. However, with so many animal rescues in Minnesota, it's likely that dogs transported from other states and countries will bring new infectious diseases to the state's canine community, she said.

"We are going to see more and more infectious diseases," Merkel said. "It is a concern."

Five things dog owners should know about canine flu

  1. Know the symptoms, which include cough, fever, runny eyes and nose, and shortness of breath.
  2. Isolate your dog from others if they're symptomatic: If your dog shows signs of a respiratory illness, isolate them from other dogs for 30 days, regardless of whether your pet is vaccinated.
  3. Consider vaccinating your dog, especially if they are high-risk or around a lot of other pups. The Board of Animal Health says to consider the dog's age and whether they are boarded often or attend community events. Dogs must receive an initial shot followed by a booster in three to four weeks, and the vaccine can cost $40 to $85 per shot, according to the agency. Talk to your veterinarian.
  4. Avoid social settings to reduce risk, such as dog parks, doggy day cares and other places dogs may have direct contact with other dogs — especially if your dog isn't vaccinated.
  5. It's not transmittable to most other pets or humans, though it sometimes can be transmitted to cats.