Emerging and New Respiratory Pathogens in Dogs

Emerging and new respiratory disease pathogens appear to be our new normal, including those in our dogs. In 2004, the first canine influenza (H3N8) appeared in Greyhounds in Florida, presumably from a mutation of the equine influenza. A second canine influenza virus (H3N2) appeared in the US in 2015. Thought to have originated in Korea, it hit the first metropolitan area in Chicago. It caused serious respiratory illness, closing down veterinary clinics, boarding facilities and doggie daycares. Research showed multiple strains were circulating.

Vaccination and Risk for Dogs

Because influenza was a new infection in dogs, nearly all dogs exposed were infected. Vaccines for both strains were developed. These were recommended for all dogs at risk, as all dogs were naïve to the virus as it emerged. It appears at this time that the H3N8 virus has disappeared. However, it is possible it will show up again. Dogs at risk include any dog in contact with other dogs – barking, sneezing, coughing, shared water and food bowls. When dogs go to dog parks, doggie daycare, the veterinary clinic, grooming facilities, dog performance activities, beer gardens, and associate with family’s and friend’s dogs, they are exposed and considered to be at risk. Any dog that Bordetella is recommended for should also have a canine influenza vaccine series with annual booster.

Fall 2024 Influenza Outbreaks and Spread

In the fall of 2024, there was an influenza outbreak on the west coast. At Veterinary Village, we identified multiple dogs who had attended a dog show on the west coast with influenza, bringing it back home to Wisconsin and Illinois.

Reports of a “Mysterious” Canine Respiratory Disease

Additionally, a “mysterious” canine respiratory disease was reported on the east coast that could not be identified as one of the dozen known respiratory diseases. Dr. David Needle and his team at the New Hampshire veterinary diagnostic lab (COLSA) are currently hard at work to identify and classify what appears to be a new organism causing this mysterious disease. It popped up on the east coast in the fall of 2024. At this point, it appears this is a mycoplasma or novel organism. It is not a bacteria, nor a virus. There are reports from multiple states including the west coast, the northern east coast and Colorado and Illinois.

Severity and Symptoms

This new organism has caused thousands of dogs to become ill, and has been fatal to some. Not only is the organism different, it does not appear to respond to antibiotics. Symptoms include runny eyes, sneezing, coughing similar to kennel cough, and fever progressing in some cases to severe pneumonia.

Vaccination Recommendations Amid Ongoing Exposure Risks

For dogs in contact with other dogs at events, daycares, dog parks, and groomers, vaccinating for influenza, Bordetella, parainfluenza, and adenovirus is strongly recommended to help prevent or reduce the severity of the illness. As with COVID-19 in human patients, co-infections with more than one infectious agent can lead to more serious disease. For this reason, protecting your dogs against the diseases we can prevent will help protect them against the multitude of diseases we don’t have vaccines for. Of these organisms, influenza is the most likely to cause serious disease. In rare cases, canine influenza can be fatal. Influenza is vaccinated for by 2 doses of an injectable monovalent or bivalent vaccine with an annual booster.

Bordetella Vaccine Forms and Delivery

There are 3 forms of Bordetella vaccines – injectable, intra-oral (in the mouth) and intranasal (in the nose). In our experience, our patients get the best protection when given the 3 way (Bordetella, parainfluenza, and adenovirus) intranasal (IN) product. We recommend only using the ADT delivery system, using no syringe, to reduce the possibility of an inadvertent injection of the intranasal product.

Lessons from Field Trial Dogs and Practical Exposure Avoidance

Several years ago, our clinic saw groups of field trial dogs who became very ill with a hot strain of parainfluenza virus. This helps us understand that even the most athletic, fit dogs are susceptible to airborne infections. Avoiding shared food and water bowls is a prudent way to minimize spread of these respiratory illnesses. Staying home if there is a local outbreak and leaving or avoiding dog events if there are coughing dogs present is prudent.

Treatment and Supportive Care

Many dogs with respiratory disease have contracted a viral or bacterial infection. If this is caused by a virus, they will not respond to antibiotics. Some dogs with respiratory disease have Bordetella, a bacteria or mycoplasma. Treatment for upper respiratory disease in dogs includes supportive care – softened dog food, fluids, cough medications, nebulizing, and possibly antibiotics if bacterial disease is suspected.

Prevention and Final Recommendations

Prevention is always best medicine. Keep your dogs up to date on all vaccines. Additionally, be attentive to current outbreaks, and keep your dogs isolated from other dogs if there is a risk in your community. If you are at a dog event or facility where there are coughing or sneezing dogs, stay home or leave immediately. Exposure is not worth the risk. Although we cannot currently vaccinate for this new organism, keeping your dog protected against other respiratory disease is important. Just like co-infections we saw during COVID-19, the same holds true. If the dog is sick with another infection, it will make him or her more vulnerable to this new and scary infection.