There has been much news coverage over the past few weeks of an outbreak of Canine Influenza in the Chicago area. Over 1,000 dogs have been affected by this contagious disease with symptoms ranging from mild respiratory signs similar to a cold, to anorexia, fevers and pneumonia. Although most dogs recover within 2-3 weeks, there have been some deaths. Over the past few years there have been sporadic outbreaks of Canine Influenza in various cities in the U.S. Most of these outbreaks have run their course without widespread and ongoing morbidity. Until this current outbreak in Chicago, all previous Canine Influenza outbreaks have involved an equine origin strain of influenza virus, H3N8. This new outbreak initially confounded veterinarians trying to diagnose the disease. It was eventually found to be an avian origin virus, H3N2, previously only reported in Asia. A new test was eventually developed to diagnose the disease.
In California, we have not seen any cases of this new strain of influenza, nor have there been any recent outbreaks of the previous H3N8 strain. A vaccine is available for the older H3N8 strain but has not been widely promoted or used, primarily due to the very sporadic and short lived nature of the outbreaks. There is no vaccine approved for the newer H3N2 strain. Veterinarians in the Midwest have used the older vaccine in hopes it would provide some benefit but, so far, there is no data to support any cross protection.
It is interesting to note that a significant number of dogs in the Chicago area that presented with respiratory symptoms tested negative for Canine Influenza but positive for other more common respiratory diseases such as Bordetella and Canine Parainfluenza and Adenovirus, three diseases for which we routinely recommend vaccinations for all our canine patients. This data reinforces how important this annual vaccine is for our pets.
Our Doctors at Harbor Animal Hospital are monitoring the reports on the influenza outbreak. We are not currently recommending the Canine Influenza vaccine for all of our canine patients, nor are the local boarding facilities requiring the vaccine as it does not appear there are any current outbreaks of the H3N8 influenza virus the vaccine protects against. If you will be traveling with your pets to the Midwest area or have any other questions regarding these contagious upper respiratory diseases please do not hesitate to call us for more information.