Canine influenza (dog flu) is a relatively new respiratory infection, with its origins traced to the greyhound racing industry in 2004. It started in Florida and spread to several states (e.g., California, Connecticut, Delaware, Hawaii, New York, New Jersey, Massachusettes) in the next few years. Places where numbers of dogs are housed together, including racetracks, shelters and pet stores, provided the conditions necessary for this highly contagious virus to spread rapidly. Also, because this virus is so new in dogs and because dogs have no natural immunity to it, almost all dogs are susceptible and have a high chance of showing symptoms if they come in contact with the virus.
Symptoms: There is a mild and a severe form of influenza in dogs. Most dogs contract the mild form, where coughing and nasal discharge persist for about one to four weeks, but dogs do well with supportive care. Some dogs develop a dry cough that is very similar to “kennel cough.”
In the more severe form of canine influenza, affected dogs will develop a high fever and may have respiratory distress, as well as pneumonia (which could be caused by a secondary bacterial infection). Even with the severe form, the fatality rate for dogs is very low (5 percent to 8 percent).
Treatment: Because this is a virus, adequate nutrition, fluids, extra attention and other supportive care can help the dogs’ immune response combating the virus. If there are signs of a secondary bacterial infection, such as a green nasal discharge, antibiotics can be prescribed. This disease has not been shown to be transmitted from dogs to humans or from dogs to other animals, but good cleanliness practices (e.g., hand washing, cleaning with appropriate disinfectants) will help stop the transmission to other dogs.
Diagnosis: As of now, there is no a quick way to confirm the presence of the canine influenza virus. By using serologic testing, antibodies to this virus can be detected within seven days after symptoms first appear. Signs of canine influenza are similar to those of many other respiratory diseases, which makes it impossible to diagnose the problem solely on clinical signs. Current testing procedures include detection of the virus itself from swabs from the nose, back of the throat or from tracheal washes, or the detection of an antibody response in paired blood samples. Because the symptoms of kennel cough are often very similar to canine influenza, sometimes veterinarians may want to do additional testing. If a dog shows respiratory symptoms and coughing but has been vaccinated against Bordetella, then canine influenza would be the likely diagnosis. For a more specific diagnosis, antibodies to canine influenza virus would further rule out kennel cough.
Prevention: The Canine Influenza Virus H3N8 vaccine is protective against the clinical signs of the canine influenza. The vaccine came out in 2009 and is considered quite safe, but like all vaccines does not offer 100 percent protection against infection. Studies have shown that the vaccine is effective at limiting the clinical signs of the disease. Owners should consult a veterinarian about the vaccination if their dog is at high risk of becoming infected, particularly if it is in close contact with other dogs at kennels or groomers or participates in shows and trials.
Dogs that are vaccinated against other more common respiratory diseases may benefit from not having the more common pathogens in their system. These dogs may have less chance of developing secondary infections. Also, if the dogs are vaccinated for other diseases, it can help them determine if the dog indeed has canine influenza or some other respiratory infection.
The focus on prevention rests on good cleaning practices and removing/isolating dogs with possible symptoms. The virus is not transmissible from dogs to other animals or dogs to humans. If a dog starts coughing or shows other signs of respiratory infection, it should probably not go to the dog park or come into contact with other dogs. This is a very contagious virus and can spread rapidly among dogs. By keeping not only the cages or other housing systems clean, but also any object dogs touch, you can effectively stop routes of transmission. Keeping clothes and surfaces clean and practicing good hand washing will also help prevent the spread of the virus. Simple bleach solutions or other disinfectants can be used to wash surfaces and objects, and use warm water and soap for hands. Actively monitoring for coughs and other symptoms will help you and your dog stay healthy. Because this is such a new virus for dogs, prevention is the best cure!
For more information: http://www.avma.org/public_health/influenza/canine_bgnd.asp.
Daniela Sharma, Ph.D. - Rutgers University
