James R. Speiser, DVM, DABVP, CCRT
April 21, 2015
Recent reports of fatal dog flu in Chicago have created a maelstrom of concern for central Indiana dog owners. Here are some important facts you need to know:
The media reported an epidemic of over 1,000 cases of flu in Chicago. There have only been a few (<12) cases of documented flu in the Chicago area, and there were only a handful of fatalities. While some of the non-documented cases may be canine influenza cases, many are not. There are many other diseases, such as common “kennel cough” caused by a bacterium called bordetella that can cause similar symptoms to mild influenza. Even if all 1,000 cases were influenza, realizing there are well over 1,000,000 dogs in the Chicago area, the incidence of influenza would be 0.1%, which is not an epidemic! There are far more fatalities from parvovirus than there are from canine influenza!
The influenza virus has many different strains that are designated with a specific letter and numbering system. The common canine influenza virus that we have seen for the past several years is a strain called H3N8. The virus that was identified in Chicago that did cause severe symptoms is a new strain to the United States called H3N2, which only resided in Southeast Asia until now. H3N2 can also affect cats.
Canine influenza causes respiratory disease, and can vary from very mild to very severe from patient to patient. Young puppies and geriatric dogs are most at risk for severe disease. Symptoms include a fever, lethargy, anorexia, runny nose, sneezing, cough, and pneumonia. Vomiting and diarrhea are NOT typical signs of canine influenza.
Purdue University has documented several cases of H3N2 canine influenza in the Tippecanoe county area, so it is traveling south through Indiana.
Canine influenza and other respiratory diseases are usually contacted and transmitted when dogs are congregating in larger numbers like at doggy daycare, dog parks, boarding and grooming facilities, or competitions. Canine influenza is spread from dog to dog through direct contact, through aerosols in the air from coughing or sneezing, sharing water dishes, etc. Clothing can carry influenza between animals, so try not to interact with known sick dogs, and wash your hands after petting or interacting with other pets
The canine influenza vaccine was developed using the H3N8 strain. It is unknown if vaccinating with the currently available vaccine will protect against the newer strain isolated in Chicago and now in Indiana. However, it is certain that the vaccine will not make dogs more susceptible. Consequently, vaccination would be prudent in dogs that are at higher risk of exposure. Pet owners must remember that it takes the immune system about 3 weeks to develop a protective immunity in response to vaccination. Because Fido got a vaccine yesterday does not mean he is protected today when he goes to the kennel! If you’re wondering if your dog should get the canine influenza vaccine, read more on our recommendation here!