Editorial: December 1, 2023

With the upcoming weeklong cluster of dog shows to be held in Orando, we thought it important to address two areas of concern for those who will be attending these events. Certainly, there is the lingering Covid-19 virus and its variants, but what really has our community concerned is the dog flu that seems to be very contagious and spreading across the country. So we have asked our Dog News veterinary columnist, Dr. Merry Fitzgerald, DVM, to guest-write our Editorial this week and answer the most-asked questions about this illness.

Is there a new respiratory illness that affects dogs?

There are reports of a highly contagious respiratory infection in dogs. As of now, it is still being referred to as the “mystery canine respiratory illness.” Outbreaks have occurred in 14 states stretching from coast to coast. States that reported cases are California, Colorado, Florida, Georgia, Idaho, Illinois, Indiana, Maryland, Massachusetts, New Hampshire, Oregon, Vermont and Washington.

The symptoms are similar to canine influenza and infectious tracheobronchitis (kennel cough) infections, but the cause of the illness has not yet been determined. There are a number of different pathogens that cause respiratory disease in dogs. These infections are usually a mixture of viral and bacterial infections.

Some diagnostics have been completed, but there has not been conclusive identification of the components causing this mystery illness. Viruses move through the respiratory system quickly and can be difficult to isolate. Sometimes these viral illnesses progress to pneumonia, which is an infection of the lungs. By this time, the offending virus is gone. This might explain why respiratory PCR panels are often negative. The testing often occurs too late to detect the inciting pathogen.

Researchers at the University of New Hampshire’s Veterinary Diagnostic Laboratory and the Hubbard Center for Genome Studies believe they have identified a new bacterium. It was found through a genetic sequencing of samples from an initial group of 30 dogs from New Hampshire that were infected last year and then an additional 40 dogs from Rhode Island and Massachusetts that got sick this year.

The pathogen is smaller than a normal bacterium in its size and the size of its genome. This makes it hard to detect and sequence. It is thought to have evolved from a dog’s normal bacterial flora.

In order to determine which antibiotics will be the most effective against a particular type of bacteria, laboratories grow the bacteria in a petri dish and then place discs containing various antibiotics on the sample and measure the response. This procedure is known as a culture and sensitivity. Researchers have not been able to grow the new bacteria in the lab.

When presented with cases of canine respiratory disease, veterinary practitioners are encouraged to perform diagnostic testing immediately, during the early stages of disease and before starting treatment. Delaying diagnostics may result in negative test results, as detection of some viruses may be inhibited by a rapid response of the immune system, and antibiotic treatment may interfere with bacterial growth and detection.

What are the signs of canine respiratory disease?

If your dog is lethargic and coughing or sneezing, he may be infected with canine respiratory disease. Other symptoms include labored breathing, fever, decreased appetite and discharge from the nose or eyes.

As the illness progresses, it tends to develop in three ways. It may cause inflammation of the trachea, which is the tube that connects the throat to the lungs. This condition may be only slightly responsive to antibiotics.

The infection can turn into a chronic pneumonia that is minimally or not responsive to antibiotics. The worst cases develop into an acute, or sudden, pneumonia that rapidly becomes severe and often leads to serious illness or death in as little as 24 to 36 hours.

What is the treatment for canine respiratory disease?

Since the agent causing the infection has not been identified, the treatment is supportive and symptomatic. This includes medication to reduce fever, if present, and antibiotics to treat any secondary infection. Most cases respond to doxycycline. Others have responded to a combination of enrofloxacin (Baytril) and amoxicillin/clavulanate potassium (Clavamox).

Your veterinarian will want to ensure your dog has adequate nutrition and hydration, which may include the use of intravenous electrolyte fluids. The placement of feeding tubes for dogs that are not eating can provide much-needed calories for recovery.

Oxygen therapy is recommended for patients with labored breathing. Your veterinarian may also recommend the use of a nebulizer, which is a drug-delivery device used to administer medication in the form of a mist inhaled into the dog’s lungs.

How can I protect my dogs against canine respiratory disease?

Respiratory diseases are spread by direct contact when a dog licks or plays with other dogs and by sharing toys or water bowls. Dogs can also spread respiratory diseases through water droplets aerosolized from sneezing and coughing.

Canine respiratory disease cases more commonly occur in dogs housed in group settings such as shelters, boarding kennels and training facilities, rather than dogs living in private homes, especially those with limited access to other dogs.

If your dog will be among other dogs at dog shows, agility trials, dog parks, doggy daycare or while boarding, consult your veterinarian about recommendations to prevent infection. Make sure your dog is currently vaccinated, especially for canine influenza, Bordetella and parainfluenza.

While the existing vaccines may not specifically target the unknown infection, maintaining overall health through routine vaccinations helps support a dog’s immune system. Dogs vaccinated against respiratory illness usually experience a milder case of the illness.

Do not share dog bowls, toys or dog chews between dogs. Until we have a better idea of what this infection is, reduce your dog’s exposure by limiting contact with other dogs outside the home.

Consult with your veterinarian if your dog exhibits any symptoms of a respiratory illness. Early diagnostics may help in getting an accurate diagnosis and treatment. Any dogs with signs of a respiratory illness should be kept at home to avoid exposing and possibly contaminating other dogs. The recommended quarantine period is 14 days.

Human health organizations monitor certain respiratory illnesses in humans, such as respiratory syncytial virus (RSV), influenza and COVID-19. At this time, no reported human respiratory illnesses have been linked to respiratory illness in dogs. Any person who develops signs of a respiratory illness who had close contact with an ill dog should consult with their physician.