A respiratory illness is spreading among dogs nationwide, including on Long Island.

Veterinarians say they're not exactly sure what the illness is, yet they believe it could be some kind of virus or bacteria they’ve seen before that has since mutated.

Dr. Jason Heller, president-elect of LI Veterinary Medical Association, says part of the reason for the spread lies in people and animals traveling more.

Dr. Heller says dog owners should be on the lookout for symptoms like coughing, sneezing, runny eyes, runny nose, lack of appetite or fatigue. Heller says it’s important to keep a close eye on the symptoms and to immediately see a veterinarian if the symptoms get worse or last for weeks.

The good news is there are some proactive steps owners can take to protect man's best friend.

"To err on the way of safety is smarter,” said Heller. “If you don't have to put your animals with other animals at this point, it might be an easier way to stay out of the line of fire. And make sure we stay vaccinated against our K-9 diseases that we can, such as influenza."

Heller says so far, there is no evidence of the illness spreading from dogs to other animals.

For the latest details about the spread of the canine illness, visit the American Veterinary Medical Association here.