Mysterious Respiratory Illness in Dogs: New Information


The mysterious dog respiratory illness is real.  There is no official data regarding how dogs have been sickened or exactly how many dogs as surveillance for companion animal outbreaks is spotty as there is no Centers for Disease Control to track data for pets. Trupanion, the pet insurance company, has made their data public. And there most certainly there is a spike in reports of respiratory signs, albeit in some parts of the U.S. and Canada – not everywhere.

Most dogs with this apparently novel respiratory infection appear to suffer a more severe and long-lasting cough (with associated signs such as mucous) compared to typical kennel cough or any of the known set of known causes for CIRDC (canine respiratory infectious disease complex). A small (but undocumented) percent of dogs develop pneumonia and require significant supportive care, and some of these dogs don’t make it through. It appears that dogs most likely to become significantly ill are dogs with another concurrent illness, and/or brachycephalic dogs (dogs like French Bulldogs, Bulldogs, Pugs, etc with limited airways).

Can Humans Infect Dogs?

So, how is this illness spread? Experts have suggested it is likely spread like other contagious respiratory infections, via the air when in close proximity to a sick dog, or even potentially (as in dog flu) a carrier who isn’t symptomatic.

However, an interesting twist comes from several rural veterinarians. Dr. Hugh Davis of Northwood, NH said that is own dogs have had zero exposure to other dogs, yet the illness occurred in his home.

Dr. Davis concedes that he might have brought home the pathogen on his own clothing (known as a fomite) or may have been exposed one way or the other through him. It appaears this is a dog illness which cannot be spread to other species, but can we spread it to dogs? He says, “A lot of cases I saw were dogs that had no exposure to other dogs, and clients who have not been around other dogs. The most extreme example was a couple with four Rotties (Rottweilers) isolated on a good-sized rural property, they hadn’t been around other dogs. My thought is that it’s human transmission via fomites (inanimate objects) or asymptomatic carriers.”

Elizabeth Gens, a certified veterinary technician in Lyndeborough, another New Hampshire rural community, suggests a similar type experience of treat significantly ill dogs who just did not have exposure to other dogs leaving her shrugging her shoulders, and unable to explain how the dogs became ill in the first place.

Dr. Davis cautions that this is his experience, and he can’t necessarily generalize beyond that. This only additional information to added into the puzzle which researchers are attempting to piece together.

It Might Be Bacterial – Not Viral

At least one group,  Dr. David Needle and colleagues at the University of New Hampshire College of Life Sciences and Agriculture, note a mysterious respiratory illness that has sickened at least hundreds and perhaps as many as thousands of dogs across the country (and dogs now in Canada) could be caused by a new type of bacterial infection that may be very good at evading the canine immune system, as well at least some antibiotics.

In a development that might help shed light on the illness, researchers at the University of New Hampshire’s Veterinary Diagnosis Laboratory and the Hubbard Center for Genome Studies say they have identified a pathogen that might be what’s making pets sick.

Through a genetic sequencing of samples from an initial group of 30 dogs from New Hampshire who were infected last year and then an additional 40 from Rhode Island and Massachusetts who got sick this year, the researchers say they have discovered a previously unknown germ.

The pathogen is “a funky bacterium,” Dr. Needle has said in press reports. “It’s smaller than a normal bacterium in its size and in the size of its genome. Long story short, it’s a weird bacterium that can be tough to find and sequence.”

However, Dr. Needle concedes his work may not completely reveal what’s happening around the U.S and also in Canada.

Experts Offer the Latest in a Free Webinar and Treatment Options

In a free webinar presented Dr. Scott Weese, an expert on infectious disease and professor at the University of Guelph Ontario Veterinary College notes that if this illness is another strain of dog influenza the effects might be expected to be more widespread that what is seen.

Dr. Weese, also the author of the Worms and Germs blog, and webinar partner Dr, Mike Lappin,  professor in Small Animal Clinical Veterinary Medicine in the Department of Clinical Sciences at the College of Veterinary Medicine & Biomedical Sciences at Colorado State University in Fort Collins and One Health Committee Co-Chair World Small Animal Veterinary Association agree that dogs with mild signs may have the “usual” and antibiotics shouldn’t be a first go-to. “Not only is there no need, more harm may be done,” Lappin says.

However, there does seem to be a degree of antibiotic resistance that might be going on with whatever this novel illness is.

Gens says, “in the summer of 2022 in southern NH, we started seeing dogs presenting with CIRDC. These dogs presented with a cough (no tracheal sensitivity), copious purulent nasal discharge, lethargy, fever. These dogs did not seem to respond at all to doxycycline. Many of these dogs developed pneumonia and required hospitalization, IV antibiotics, oxygen therapy, etc. We did have a few cases of dogs that passed away as a result. We started treating them with a combination of Amoxicillin/Clavamox  and Enrofloxacin. We kept these dogs on this protocol until one-week after resolution of clinical signs.”

However, all these antibiotics have potential adverse responses – and each case is individual and dependent on individual veterinary input.

Spreading like wildfire online is word that an antibiotic drug called chloramphenicol which can treat this illness, curing at least one dog. However, that’s one dog. What’s most important is that this drug – even if effective – should be a last resort not a first resort as it has potential dangerous side-effects and must even be handled with extreme care by humans before administering.

Another online rumor is that the human antiviral drug Paxlovid is a good idea – though it likely is not.

Stop Going to Public Dog Events and Limit Social Exposure

Experts agree to be careful about exposing your dog to others, particularly older dogs, brachycephalic dogs and dogs with other illnesses. This means that dog shows (unless outdoors – and even then judges should wear gloves and other precautions should be taken etc) and other indoor dog events should like be cancelled (something the American Kennel Club is not likely to do). At least some very sick dogs have apparently become ill via exposure at dog shows.

You can watch the free webinar HERE with Drs. Weese and Lappin and also Dr. Carrie Jurney is a veterinary neurologist and practice owner at Remedy Veterinary Specialists in San Francisco and Dr. Steve Weinrauch, Chief Veterinary/Product Officer of Trupanion.

More on what pet parents need to know.