STORY: There’s a mystery illness popping up across the United States – in dogs. Symptoms include coughing, which can last four to six weeks. “Cough, lethargy. Sometimes they'll like hack up a little bit of foam, exercise intolerance, sometimes decreased appetite.” And it can be fatal – though vets like Matthew Goss say there’s no need to worry too much. “No real need to panic. It's not something that's going to take a dog's life like that. It's going to be something that if you're going to notice, they're getting worse, you should at least have time to get checked out, get medications on board.” It’s been found in at least 14 states already, with Oregon reporting some 200 cases. And the American Veterinary Medical Association is now asking vets to report cases while laboratories race to isolate the pathogen. “It appears to be potentially an atypical course of a respiratory disease in dogs. And that's what has us most alarmed is - the typical course, we're used to that - but these cases tend to be testing negative to our normal agents that cause the disease and have a really prolonged course of the disease up to 4 to 6 weeks.” That’s Rena Carlson, the association’s president, who says researchers are still trying to figure out if the disease is viral or bacterial. One possibility: it could be a variant of a well-understood canine disease dog owners may know as “kennel cough”. Some acute cases have quickly become pneumonia within 24 to 36 hours, according to the association. The disease has already been reported for months.So far, there are no signs it's jumping to humans. Still, Carlson is urging caution. “Make sure you've got 'em vaccinated for our known diseases. The better they can fight off our typical diseases, the better they'll be able to fight off anything new.” Ahead of the holiday season, vets are also warning dog owners to take extra care to prevent any spreading - at a time when people often take pets traveling or place them in kennels when they go away.