Oregon dealing with respiratory illness incidents in dogs

The cause behind a canine infectious respiratory disease that began circulating in the Portland metro and Willamette Valley areas of Oregon a few months ago remains a mystery.

The Oregon Department of Agriculture (ODA) has received more than 200 case reports from veterinarians since the middle of August, said Andrea Cantu-Schomus, communications director with the ODA, on November 16.

Dr. Ryan Scholz, Oregon state veterinarian, is working with reporting veterinarians and specialists at Oregon State University’s Carlson College of Veterinary Medicine, the Oregon Veterinary Diagnostic Laboratory (OVDL), and the Department of Agriculture’s National Veterinary Services Laboratory (USDA NVSL) to find the causative agent behind these cases.

“Based on the epidemiology of the cases reported at this point, the cases appear to share a viral etiology, but common respiratory diagnostic testing has been largely negative,” Cantu-Schomus wrote in an email. “A handful of cases do test positive for M. cynos, but that agent is not believed to be the underlying causative agent.”

The cases reported to ODA appear to primarily fall within the following clinical syndromes:

• Chronic mild to moderate inflammation of the trachea lasting six to eight weeks or longer, which is minimally or not responsive to antimicrobials.
• Chronic pneumonia that is minimally or not responsive to antimicrobials.
• Acute pneumonia that rapidly becomes severe and often leads to poor outcomes in as little as 24 to 36 hours.

The ODA spokesperson is asking veterinarians to report cases to the department as soon as they can and recommending that pet owners consult their veterinarian if they suspect their dog is ill.

“Because of the broad spectrum of potential respiratory diseases, there is no one-size-fits-all recommendation, and working with a veterinarian is the best way to ensure that owners have accurate information that is appropriate for their situation,” she said.

Dr. Kurt Williams, director of OVDL, said in a November 14 news interview that owners should ensure their dogs are fully vaccinated and to avoid contact with other dogs from outside their household until the illness is contained.

The ODA is working with pathologists and virologists at the OVDL as well as the NVSL to implement a diagnostic testing plan in these cases. Complicating matters, however, is that in most cases tested to date, it appears that the period of shedding may already be passed by the time cases are seen by the reporting veterinarians.

To address this limitation, the ODA has connected with several emergency veterinary practices to begin widespread sampling of potential respiratory cases, which will be paired with PCR testing using generic primers, virus isolation, and rapid whole genome sequencing in hopes of diagnosing an etiologic agent.

The ODA is also working with an animal rescue entity in the Salem area, which had several cases within their rescue population, to collect samples for serology. The OVDL will be testing these samples using broad serologic tests to hopefully narrow down the pool of potential etiologic agents, Cantu-Schomus said.