What We Know About the Mysterious Respiratory Illness Affecting Dogs

A mysterious respiratory illness that has been sickening dogs continues to spread across the United States while veterinarians try to determine its causes and the best methods for treating it.

The symptoms are similar to kennel cough, an upper respiratory infection, but can last much longer and, in some cases, prove fatal, according to veterinarians.

Here is what we know:

What are the symptoms?

The infected dogs develop a cough, fever, lethargy and intermittent loss of appetite. While infected, some dogs will develop pneumonia. Veterinarians have reported seeing blue and purple gums in those cases.

Dogs with kennel cough may show some of these symptoms, such as coughing, lack of appetite, fever and lethargy. If it’s kennel cough, the symptoms usually clear up in one to three weeks. With the latest respiratory illness, however, veterinarians are reporting that dogs can have symptoms for six weeks or more.

Where has this been reported?

The illness has been found in at least seven states: Colorado, Massachusetts, Oregon, Rhode Island, Illinois, Maryland and Wyoming.

It’s unclear how many dogs in total have been infected, because there is no official count of the cases.

The cause is not clear.

It’s unclear what causes the illness. Researchers are still running tests to learn more about the illness.

There is some disagreement on whether the illness is caused by a virus or by bacteria.

Dr. David Needle, senior veterinary pathologist at the New Hampshire Veterinary Diagnostic Laboratory of the University of New Hampshire, said that he believed the illness was being caused by a bacteria, based on what he had seen in his area.

Some veterinarians in Oregon hypothesize that it could be viral, because the dogs they have treated have not responded to antibiotics.

“I’m open to it being either, and I’m open to it being something we’re not even thinking about,” said Dr. Kurt Williams, director of the Oregon Veterinary Diagnostic Laboratory at Oregon State University’s Carlson College of Veterinary Medicine.

Researchers strongly agree that dogs are most likely to develop the illness when they have been around other dogs.

Dr. Lindsey Ganzer, a veterinarian and the chief executive at North Springs Veterinary Referral Center in Colorado Springs, Colo., said that all of the dogs she had treated for the illness had spent time in places with high concentrations of dogs, such as boarding facilities, doggy day care centers or dog parks.

Dr. Ganzer said she feared that veterinarians might see an increase in cases as more owners board their dogs or send them to day care during the holidays.

“We’re really hoping just with getting the word out there that people are less inclined to do that,” she said. “The veterinary community as a whole is kind of scared.”

What should owners do?

Don’t panic, and isolate your dog if it is showing symptoms.

Dr. Stephen Kochis, the chief medical officer for the Oregon Humane Society, said he did not want people to be alarmed by the new illness, because the overall number of dogs with respiratory illnesses had not increased. If dogs are showing symptoms, there are steps owners can take to be proactive, he said.

“All of us have gone through Covid,” he said. “I would say if your dog is showing signs of respiratory disease, isolate them in the home, call your vet, get them seen.”