By Brooke Garcia, CVT

Colorado State University researchers are investigating whether a contagious illness that has led to a spike in the number of upper respiratory infections in canines along Colorado’s Front Range is due to a new pathogen or an organism that is already known and recognized as a cause of respiratory disease in dogs.

In addition to seeing more cases, the current wave of canine respiratory disease has differed from previous versions. Dogs are experiencing prolonged coughs, up to several weeks, and more cases are developing what appears to be a secondary pneumonia. In September, October and November of this year, CSU’s Veterinary Teaching Hospital has seen more than double the cases of canine pneumonia compared with the same period in 2022. Some cases have been fatal.

Researchers in CSU’s Center for Companion Animal Studies are working with the university’s Veterinary Diagnostic Laboratory and the State Veterinarian’s Office to investigate each case of pneumonia from those three months. The team should know more about the origins of this version of the disease in the coming weeks.

“Contagious respiratory disease in dogs (kennel cough or the canine infectious respiratory disease complex) is common and there are multiple viral and bacterial causes,” said Dr. Michael Lappin, board-certified internal medicine veterinarian at the CSU James L. Voss Veterinary Teaching Hospital. “However, in recent months, cases are being diagnosed more frequently and the course of disease is different than usual, surprising both pet owners and veterinary health care providers. It is currently unknown whether these unusual cases are caused by a virus or a bacterium, or a combination of both types of infection.”

In addition to Colorado, cases of canine respiratory disease have also spiked elsewhere across the country, including Oregon, California, Florida and New Hampshire, as well parts of Canada. Lappin said it is too soon to determine whether canine respiratory disease cases will go up or down heading into the December holiday season.

The CSU investigative team will look at whether the disease appears to impact certain types of dogs more than others. There is, however, no evidence to suggest the cause of this syndrome is a pathogen that affects people.

Dr. Gillian Gwartz, program veterinarian in the State Veterinarian’s Office, said that although the state doesn’t have specific numbers of cases, anecdotally the office has also seen an increase in the number of vets calling in to report respiratory disease.

“CSU has been instrumental in helping increase diagnostic testing in hopes of finding a primary cause of the outbreak,” Gwartz said. “We still don’t have a single conclusive causative agent, but we’re working with select vet clinics to try to get more samples to see if we can find a pattern.”

Recommendations for keeping dogs safe

Dr. Amanda Cavanagh, board-certified emergency veterinarian and head of the CSU Small Animal Emergency and Urgent Care service, is eager to better understand the data surrounding the disease to help inform treatment. “The health and well-being of our canine companions are paramount,” Cavanagh said. “We are actively learning about this illness, its causes, transmission, and potential treatment measures to protect our beloved pets.”

The mode of transmission remains unclear, but early observations indicate it appears to be contagious and most likely from direct contact with other dogs. CSU veterinarians are treating patients in isolation to contain the spread.

Current recommendations for pet owners include:

• Keep vaccines updated: Ensuring dogs are up to date with vaccinations is critical. While the existing vaccines may not specifically target this unknown infection, maintaining overall health through routine vaccinations can help support a dog’s immune system in combating various infections. Optimal protection against common respiratory infections includes the annual intranasal vaccine for Bordetella, Adenovirus 2, and parainfluenza vaccine, combined with the injectable influenza H3N2 vaccine. Avoid bringing a dog into the community until two weeks after the last dose of a vaccine and immunity has developed.
• Watch them closely: CSU veterinarians advise pet owners to monitor their dogs closely for progressive coughing that may be accompanied by signs of ocular or nasal discharges and sneezing.
• Consult your veterinarian: If these clinical signs develop, consult your veterinarian immediately, particularly if your dog concurrently loses its appetite, has trouble breathing, is coughing continually, or is extremely lethargic.
• Avoid voluntary gatherings of dogs: For the time being, it would be prudent to avoid dog parks and other social events where your dog could have contact with dogs of unknown vaccination or health status. If boarding, daycare or grooming are required, complete the vaccinations described above before attending.

Ongoing research and collaborations

CSU has a team of researchers in the Veterinary Teaching Hospital, the Veterinary Diagnostic Laboratory and the Translational Medicine Institute that are actively working on canine infectious respiratory disease complex, including Lappin. The university is collaborating with the Colorado State Veterinarian’s office, the USDA and the Colorado Veterinary Medical Association to collect more data and share information to pet owners and veterinary health professionals in Colorado and other states. Funding to provide free diagnostic testing for select cases in Colorado is currently provided by a collaboration with Zoetis Animal Health.

As researchers intensify their efforts to identify the cause, pet owners are encouraged to stay informed and adhere to any guidelines provided by veterinary professionals.

Christopher Outcalt contributed to this report.

Brooke Garcia is the social media manager for the CSU College of Veterinary Medicine and Biomedical Sciences, and a certified veterinary technician.