(KRON) — Respiratory illnesses aren’t just hitting humans hard this year — there’s been a spike in dogs getting the flu as well.

Outbreaks are being reported in several states, including California. Vets across the country are warning people about canine influenza in the hope that they will keep their four-legged friends from getting “sick as a dog.”

They say the disease is highly contagious. One dog walks into a kennel with it and all the dogs walk out of the kennel with it.

Worse, dogs can spread the virus even if they have no symptoms, which can include cough, runny nose, fever, loss of energy and lack of appetite.

One vet told KRON4, “Twenty percent of those dogs are going to remain asymptomatic and that poses a problem when you have 20% of the dogs that can spread and are highly contagious, that’s going to be driving the outbreak.”

Scott Schrank, the owner of Fog City Dogs in San Francisco, says he follows canine influenza news closely. He says despite outbreaks happening nationwide – there is some good news.

He told KRON4, “I don’t think we’ve seen a huge amount of influenza cases in or around the bay.”

Schrank also says cases tend to stay very local because dogs don’t travel like humans. The doggy daycare is still doing what it can to prevent it.

“We maintain high cleanliness standards in the building. We’re cleaning religiously every single day and any dogs who are presenting with any sort of respiratory symptoms, we’ll notify their owners and put those dogs into isolation to keep away from other dogs in the building,” he said.

Fog City Dogs requires all dogs to be vaccinated against canine influenza, which vets say is the best way to prevent it. But, you should also watch your dog carefully for symptoms if they socialize with other dogs.

KRON On is streaming news live now

“If you’ve had your dog in a kennel or a dog park or grooming with other dogs and three to five days later they’re coughing and show respiratory signs then you definitely want to have them checked by a veterinarian,” Schrank said.