ATLANTIC — Researchers think a new type of bacterial infection could be what is causing an illness that is sickening dogs across the country.

The illness — which causes a cough that can last for weeks — has resulted in the deaths of some dogs.

The pathogen researchers have identified is small, making it hard to find.

Mike Stephen of the USDA Animal and Plant Health Inspection Service said the agency is working with multiple state animal health officials and diagnostic labs regarding the respiratory illness.

The disease has already shown up in Des Moines, with local vets dealing with cases of it around southwest Iowa.

The sick dogs exhibit symptoms that include things like coughing, sneezing, nasal discharge, eye discharge and lethargy. It can include a respiratory illness or pneumonia that doesn’t respond to antibiotics, which can can be fatal for the dog.

Veterinarian Melissa Beyer of the South Des Moines Veterinary Clinic reported that the symptoms are common for many illnesses, but if she tests for those illnesses, they come back negative.

“That’s where it’s hard because something is causing a cough, but we don’t know what yet,” Beyer said.

Dog owners are encouraged to keep their dogs immunizations up to date, and to avoid contact with other dogs, especially if they are showing symptoms. If your dog is showing symptoms, seeing your vet as soon as possible is important.