Friday, November 18, 2005


Canine Influenza:
What You Need To Know

This stylized image of a single influenza virion is shaped like a globe with a halo of projections, an innocent looking blue golf ball with tiny tees sticking out of it. These viruses, however, when they travel in groups become important diseases in mammals and birds. The primary source of influenza A viruses is aquatic birds which migrate from continent to continent. Other animals susceptible to influenza include humans, domestic birds, mink, seals, whales, pigs, and horses. Recently an equine influenza virus has been found in dogs.

The case of a virus crossing a species barrier is very uncommon and causes high concern in medical circles. Some of this concern has been triggered by the recent crossing of bird flu into humans. This is why the Center for Disease Control has become involved in monitoring cases where viruses cross species boundaries. The CDC is monitoring all such cases including canine influenza.

The canine influenza virus was first detected among racing greyhounds in Florida and other states where Greyhounds race. The virus is thought to to be related to equine influenza which has a vaccine available and has been known in horses for over 40 years. Canine influenza is being studied in various places including the University of Florida’s College of Veterinary Medicine and the Cornell University College of Veterinary Medicine, Dept. of Population Medicine and Diagnostic Sciences. A recent test summary issued by the Cornell Department of Population Medicine and Diagnostic Sciences, on November 4, 2005 identified 232 cases of positive samples for Canine Influenza from 1224 samples submitted.

Geographic distribution was fairly wide ranging and included 16 states from New York to California. The state with the highest number of cases was found in Florida with 92, followed by New York City (46), New York State (31), California (15), New Jersey (13), Connecticut (9), Massachusetts (6), Washington, D.C. (5), Arizona (4), Washington State (3),Ohio (2), North Carolina (2), Georgia (1), Wisconsin (1), Oregon (1), Pennsylvania (1). These results, however, only reflect samples that were submitted to the laboratory for testing.

Signs and Severity of Canine Influenza

The symptoms of canine influenza may mirror signs of kennel cough and include sneezing, coughing and fever. Fever may be high and range from 103 to 105; these fevers require immediate veterinary attention. Nearly 100 percent of the dogs that come into contact with the virus become infected regardless of vaccination history.

Approximately 20 percent of dogs infected will not exhibit symptoms. Of the 80 percent that exhibit symptoms two forms have been observed: Mild infection – Symptoms include a low grade fever, nasal discharge, and a persistent cough that can last up to three weeks. Severe Infection – Symptoms include a high fever, increased respiratory rates with difficulty breathing and other indications of pneumonia. Researchers have reported that canine influenza is fatal in fewer than 8 percent of infected dogs. Because this virus is new to dogs, most dogs will not have a natural immunity to the illness.

Diagnosing Canine Influenza
A diagnosis of canine influezna infection is done by detecting antibodies to the virus. Serum samples from sick and recovering dogs can be collected and sent to the Animal Health Diagnostic Center at Cornell University. Serum samples from recovered dogs can be submitted and will determine previous exposure to the virus. Collection of a pharyngeal (not nasal) swabs or tracheal swabs on dogs with fevers very early in the disease may help chances of confirming the
presence of the virus. Tissues from dogs that have died suddenly with acute respiratory signs should also be submitted (shipped in overnight cold pack).

Treatment of Canine Influenza

Your veterinarian should be contacted immediately if you think your dog may have contracted canine influenza. Your veterinarian will also be able to make recommendations regarding the symptom free dogs you may have in your household. Although most dogs will recover from the virus without any treatment, dogs showing symptoms of even mild infection can be treated with antibiotics to prevent secondary bacterial infections. Those with a more severe form of the virus will require the same treatment as humans with influenza including fluids and rest. More severe cases will require IV fluids and antibiotics. Treatment has been successful in 95 percent of cases to date.

How Canine Influenza Is Spread

The virus is thought to be mainly airborne, most likely transmitted by infected dogs sneezing or coughing on each other. Dogs become symptomatic in two to five days after exposure to an infected dog. Infected dogs have the ability to spread the virus for seven to ten days after the onset of symptoms. As in human influenza the virus can be spread through direct contact with an infected surface. Prevention can be helped by washing hands after handling dogs and washing exposed surfaces with a detergent or mild bleach solution. Infected dogs that do not exhibit symptoms, (20 percent), are still able to spread the virus.

Prevention of Canine Influenza

Although vaccines for this disease are in the research stage, there is no vaccine available at this time. Using common sense is a key to preventing the spread of this disease. Watch for news of outbreaks in your area, check with your veterinarian to see if cases have been reported in your area. If you use a boarding kennel, grooming shop or dog training class ask them about what precautions they are taking to isolate any apparent cases. If your pet has a respiratory infection or is recovering from one, limit its contact with other dogs for a couple of weeks to allow for complete recovery. Assume that the more exposure your dog has to other dogs the greater the chance of becoming infected. With higher exposure such as dog shows and other events you will need to take more care regarding sanitation, hand washing after handling other dogs, and care when selecting areas to exercise your dog.
Usually this disease is self limiting and most dogs will recover in 2-3 weeks. There is no cause for panic among dog owners. However, there is cause for common sense and observation by dog owners, particularly in those cases where dogs are gathered in groups. Dog owners should be aware of situation in their area and maintain communication with their veterinarians.


American Veterinary Medical Association,
Cornell University College of Veterinary Medicine,
Florida State University, College of Veterinary Medicine,
National Institute of Allergy and Infectious Diseases, NIH,
University of Illinois College of Veterinary Medicind,


Center for Disease Control and Prevention: 800-243-2343
American Boarding Kennel Association: 877-570-7799 -

On-Line Resources

Center for Disease Control and Prevention (CDC) Media Briefing Transcript, 9/26/05,

University of Florida Canine Influenza Virus Fact Sheet

Cornell University Canine Influenza Information

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