KSDK - Flu season is here and not just for people. Cases of dog flu are popping up all over the country.

Veterinarians 5 On Your Side spoke with said some cases have been reported in the St. Louis area earlier this year, and they’re asking owners to get their pets vaccinated. The annual vaccine comes in a two-part series.

“If you go to the dog park, if you go to parks, if you boarding or grooming or pet daycare, having the dog vaccinated is the most important step,” said Dr. Kelly Ryan, the director of the Animal Medical Center of Mid-America.

Related: Veterinarians warn of dog flu spreading around STL area

Ryan said the virus is transmitted mainly through nasal discharge, coming from another dog or object, like chew toys or dog bowls.

The symptoms include sneezing, a dry cough, loss of appetite, and watery eyes. A runny nose can be another symptom, but some of the signs are behavioral. Dr. Ryan said 25 percent of dogs who carry the virus won’t show any symptoms. And, there are no cures.

“The dogs that are dying from the disease get secondary complications. It starts with sneezing or coughing, but can be debilitating pneumonia quickly,” said Dr. Ryan.

Canine influenza is highly contagious among dogs for a three-week period, which means other dogs could easily get it in the veterinarian’s waiting room.

"The point where you would wanna worry and call your vet to get in for an appointment would be if your dog stops eating, or loses their energy levels, stops wagging their tail, kind of doesn't have that same pep in their step that they usually have," Dr. Andrea Sanchez with the Banfield Pet Hospital said.

For more information on protecting your pets from the flu, click here.