Canine Influenza Virus H3N8
October 6, 2005
Contributed by TJ Morgan, AAS.
Practice Manager, Neel Veterinary Hospital
A media briefing from the Centers for Disease Control addresses the newly identified canine influenza virus H3N8. In this September 26, 2005, discussion the participants were directly commenting on the questions and issues that were brought up by the Science Journal article, "Transmission of Equine Influenza Virus to Dogs."
The major emphasis and studies concerning this recent discovery is focused on the development of an equine virus, how it was transmitted to canines, and the implications concerning the possibility of human infection. The authors of the paper Dr. Ruben Donis, Centers for Disease Control; Dr. Nina Marano, Centers for Disease Control; Dr. Cynda Crawford, University of Florida College of Veterinary Medicine; and Dr. Ed Dubovi, Cornell University Animal Health Diagnostics Center all agree that there is a very small likelihood for the transmission of equine influenza to humans.
The H3N8 virus has been present in horses for over 40 years. The first identified incident of the H3N8 canine influenza virus was at a Florida greyhound racetrack in January, 2004. From April to May of 2005 samples were submitted from the pet sector of the canine population and were positively tested as being canine influenza virus. It is unknown exactly how widespread H3N8 is in the canine population across the United States but there have been verified cases in the New York City area with one possible canine patient in the state of Massachusetts. Dr. Ed Dubovi from Cornell University Animal Health Diagnostics Center states that there are more samples on their way for testing from various locations across the country.
The canine influenza virus presents itself clinically much like that of the bordetella bronchiseptica bacterium which is much more commonly referred to as kennel cough. What has been noted is that many dogs that are infected with the canine influenza do not exhibit overt symptoms and therefore are not brought to veterinarians for treatment. Dogs infected present with a characteristic cough that is associated with bordetella bronchiseptica and may also have a slight fever and a nasal discharge. A complication that is associated with the influenza infection is pneumonia. There have been a small number of fatalities reported that are attributed to the development of pneumonia in the canine patient. While a high number of deaths were witnessed from a very small outbreak in a Florida greyhound racing facility Dr. Cynda Crawford, from the University of Florida’s College of Veterinary Medicine, expects an actual mortality rate of 6 to 8 percent from this virus. Dr. Crawford admits that due to the developing data that these numbers could change.
Dr. Nina Marano from the Centers for Disease Control advises pet owners to exercise common sense. Additionally, Dr. Marano states, “if your dog is exhibiting any signs of a respiratory illness, you certainly want to get some advice from your veterinarian”. According to Dr. Marano, pet owners should keep their dogs at home if they currently have a respiratory infection or are recuperating from an infection for at least a “couple of weeks”. Dr. Marano reiterated that common sense was a good guideline to follow and that pet owners should continue their daily activities with their pets, such as going to dog parks and other dog-related activities unless their pet has a respiratory infection, or is recovering from one.
Most pets receive annual vaccinations which protect them from contracting many diseases. The parainfluenza virus is usually a part of the yearly vaccination regimen but H3N8 is not related to it and in fact is very different than parainfluenza. Some veterinarians also routinely vaccinate for bordetella bronchiseptica bacterium or kennel cough. Neither of these vaccines will protect dogs against the canine influenza virus. At this time, a vaccine for canine influenza virus has not been developed.
Pet owners should contact their veterinarian if their pet exhibits any respiratory symptoms. Pets should receive a thorough physical exam by a veterinarian who will then be able to prescribe a treatment regimen according to their physical findings. Dr. Crawford urges pet owners to keep their pets vaccinated because ”it may be that bordetella bronchiseptica and/or parainfluenza virus may turn out to be the more common causes of kennel cough”.
Original text for this article can be found at DogsCatsKidsLife
, the Blog of TJ Morgan.