16 States Where Mystery Dog Illness Is Now Spreading

Veterinarians still don't know exactly what's causing this respiratory illness in dogs.

We tend to view our pets as part of the family, which is why we would do anything to protect our pups. Depending on where you live, extra caution may be in order right now, as a mystery dog illness has been reported in dogs across the country. To be clear, the unknown affliction could strike dogs anywhere, but so far, veterinarians have detected its spread in 16 states. Read on to learn more about the illness, and where it's making dogs sick.

RELATED: Mystery Dog Illness Spreading Across the U.S.—These Breeds Are Most at Risk.

The mystery dog illness was first reported in Oregon.

Close up of white Labrador dog at vet clinic with female owner petting him, copy space

An unusual bout of respiratory disease is causing concern among the canine community. Now referred to as atypical canine infectious respiratory disease complex (aCIRDC), this mystery dog illness was first reported in Oregon over the summer, according to the Johns Hopkins Bloomberg School of Public Health. It quickly started circulating within the state, but the American Veterinary Medical Association (AVMA) said the exact cause of this specific disease is still unknown.

"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," Andrea Cantu-Schomus, communications director for the Oregon Department of Agriculture (ODA), told the AMVA on Nov. 16. "A handful of cases do test positive for [the bacteria] M. cynos, but that agent is not believed to be the underlying causative agent."

As health experts continue to try to understand aCIRDC, the illness has spread beyond state lines.

RELATED: Early Warning Signs of the Mystery Dog Illness Sweeping the Nation, Expert Says.

It has now been found in 16 states.

A beagle sleeping on his back on the couch.
Przemek Iciak / Shutterstock

Veterinarians in Oregon have reported over 200 cases of aCIRDC since Aug. 2023, according to the ODA. But while this state may have the highest prevalence so far, it is no longer the only one with reports of the mystery illness.

In a Dec. 4 press release, the LSU School of Veterinary Medicine revealed that aCIRDC has now been found in a total of 16 states: California, Colorado, Florida, Georgia, Idaho, Illinois, Indiana, Maryland, Massachusetts, New Hampshire, Nevada, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington.

In the Dec. 5 episode of the John Hopkins podcast Public Health On Call, Meghan Davis, DVM, a veterinarian and assistant professor of Environmental Health and Engineering, said that we still don't know just how many dogs have fallen sick from this disease in the country.

"We've had reports of mysterious illness in multiple states, but it appears to be a bit worse on the West Coast of the U.S.—a lot of the cases so far have been in Oregon," she shared.

RELATED: 5 Best Ways to Protect Your Dog From the Deadly New Mystery Illness Spreading.

There are specific symptoms you can watch out for.

sick dog at the vet
FamVeld / Shutterstock

While there is still so much unknown about aCIRDC, there are some clear signs that have been linked to this mystery illness.

"The symptom we've associated most with this disease is cough," Davis said. "But having a cough doesn't necessarily mean that a dog has this particular syndrome. A cough can also be seen in many other fairly common illnesses that dogs get, like kennel cough."

Lori Teller, DVM, clinical associate professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, told CBS-affiliate KBTX that alongside a cough, pet owners may also notice a runny nose with aCIRDC. And over time, dogs might continue to appear sicker.

"In more advanced cases your pet may not want to eat, just may be lethargic and lying around, and in really advanced cases have a difficult time breathing and have developed pneumonia," Teller noted.

Vets are advising pet owners to be cautious.

Silhouettes of runner and dog on field under golden sunset sky in evening time. Outdoor running. Athletic young man with his dog are running in nature.

The thought of a mystery dog illness spreading across the U.S. might strike fear in any pet owner's heart. But the experts at the ODA said they "suggest caution rather than worry."

If you notice any of the symptoms associated with aCIRDC, you should take you dog to the vet for a check-up. Otherwise, there are several precautions you can take in order to try to protect your pup.

The first thing the ODA advises dog owners do is make sure their pet is up-to-date on all the vaccinations recommended by their veterinarian.

"This may include vaccinations for canine influenza, Bordetella, parainfluenza and canine adenovirus type 2," according to the health department.

You should also be more cautious about your pup using communal water bowls and toys, as well as avoid putting them in settings where they may be exposed to unknown dogs.

"Socialization is important for your dog, so you might consider creating a playgroup of known dogs that are also vaccinated," the ODA suggests.

RELATED: For more up-to-date information, sign up for our daily newsletter.

Kali Coleman
Kali Coleman is a Senior Editor at Best Life. Her primary focus is covering news, where she often keeps readers informed on the ongoing COVID-19 pandemic and up-to-date on the latest retail closures. Read more
Filed Under
 •  •  •
Sources referenced in this article
  1. Source:
  2. Source:
  3. Source:
  4. Source:
  5. Source: