Published 12/8/2023

An atypical canine infectious respiratory disease reported in 12 states across the United States currently does not seem to be affecting dogs in Missouri. Canine infectious respiratory disease is common and can be caused by a variety of different, already documented, pathogens, including viral and bacterial agents. Some of these are endemic, meaning there are rising and falling numbers of cases at various times of year in different locations — similar to the common cold in people.

Canine infectious respiratory disease cases recently reported in Oregon, Colorado, and New Hampshire are noteworthy because progression and response to treatment differ from what veterinarians are accustomed to seeing, according to reports. Lauren Delaney, DVM, client services veterinarian at the University of Missouri Veterinary Medical Diagnostic Laboratory, said many labs are working to identify the causative agent.

“So far, the scientific community does not have an answer,” said Delaney. “Officials in Oregon and at Colorado State University are worried about a viral cause, while the New Hampshire Veterinary Diagnostic Laboratory has identified DNA fragments from a bacterial organism that has not been previously described in coughing dogs. In the absence of a causative agent, we can’t say for sure if this is something new, or even if all these cases are related. This also makes it impossible to confirm new cases in new areas. We rely on our practicing veterinarians to tell us when something seems atypical and on our routine testing to rule out the usual suspects. Meanwhile, the scientific investigation is ongoing.”

Carol Reinero, DVM, PhD, DACVIM, and Aida Vientós-Plotts, DVM, PhD, DACVIM, professor and assistant professor of small animal internal medicine respectively, who co-founded MU’s Respiratory and Aerodigestive Disorders Specialty Clinic or BREATHE Clinic, explained that much is still unknown about the respiratory disease cases.

In a written statement they noted, “If there really were a brand-new mystery pathogen that dogs had never been exposed to before, we would expect dogs to have no immunity against it. This would likely translate into widespread infection and not just pockets of disease as we’re seeing in some states, but not others. At the University of Missouri, we are not documenting an increase in canine infectious respiratory disease cases or infectious pneumonia any more than we have seen in other years. In fact, the cases we have recently seen where signs were suspected to be caused by the disease, with diagnostic testing, we’ve shown they have other diseases. This is likely because the media-reported outbreaks of respiratory disease in dogs have increased owner awareness of respiratory clinical signs in their dogs.”

Elizabeth Easley, DVM, clinical instructor of small animal emergency and critical care at the MU Veterinary Health Center, agreed. “Currently, the respiratory cases we’ve seen this year are no different from any other year,” said Easley. “There is a lot in the media that is causing people to worry, but on the clinical side we are not seeing anything different than any other winter. I would encourage people not to panic and to just take normal precautions.”

According to Reinero and Vientós-Plotts, while the causative agent is at present undetermined, a known pathogen could still be the cause but not present in swabs and samples tested. This could be due to the pathogen not shedding at the time or not being present in the nose where the sample was collected, but instead in the lungs. Several laboratories have been collecting samples from the nose and mouth of dogs with a variety of respiratory diseases, and there have been reports of one bacterial organism, IOLA KY405, that appears to be novel. However, Reinero and Vientós-Plotts noted that the identification of an organism does not mean that the organism is the causative agent of disease.

“These findings need to be interpreted in context of clinical and laboratory findings for each of those patients,” they wrote. “There are a large number of bacteria that inhabit the lungs as part of the normal flora. Many of the studies describing those bacterial populations have been performed in research dogs and there is not enough literature available that includes more information regarding the bacterial populations of pet dogs from different parts of the country. Additional studies are needed to help us figure out if the newly identified IOLA KY405 contributes to respiratory disease in dogs.”

In the meantime, Delaney recommended owners ensure their pets are properly vaccinated and contact their veterinarian with any concerns. If pet owners are uneasy, they should consider avoiding boarding facilities, dog parks, and other locations where dogs from different households comingle.

Easley said there are not many specific prevention tactics that pet owners can take other than staying up to date with vaccinations and considering a cool-water humidifier in the house as it gets dry.

Reinero and Vientós-Plotts emphasized continuing pets’ regular wellness care, including vaccination against pathogens that cause canine infectious respiratory disease. This is especially important for puppies, geriatric dogs, dogs predisposed to respiratory disease, dogs with chronic respiratory signs like coughing, noisy breathing, difficulty breathing, or exercise intolerance, and dogs with known immunodeficiency or immunosuppressive disorders.

“We strongly discourage the routine use of antibiotics in all cases of canine infectious respiratory disease, as viruses are not treated with antibiotics and most cases resolve on their own,” they added. “Dogs with the disease benefit from supportive care, including airway humidification, minimizing triggers of cough and support of hydration. Owners of dogs that develop more severe signs, such as lethargy, rapid or difficulty breathing, and loss of appetite should consult their veterinarian for evaluation and further care. It is also important to note that respiratory clinical signs may be due to a variety of other respiratory and heart diseases, and if severe or chronic, can also warrant a visit to the veterinarian.”

By Nick Childress