Every now and again I will be presented with a lethargic, coughing dog with a fever and I am asked if this could be the dog flu. Yes, dogs do get the dog flu, more appropriately known as canine influenza. There has been increased media coverage of this disease over the past year because a new strain and outbreak of this was found in Chicago in March 2015. Fortunately, as yet, the virus has not established itself in Canada.
Although this blog is about canine influenza, I want to stress that this is more of an educational piece. Canine influenza is an emerging disease that needs continued surveillance but fortunately, at this time, is of minimal concern in Canada.
Regardless, let’s answer some of the questions you may have about the dog flu:
What is Canine Influenza?
Canine influenza, or dog flu, is caused by the canine influenza virus. It is highly contagious and easily spread from infected dogs to other dogs through direct contact, nasal secretions (through barking, coughing or sneezing), contaminated objects (kennel surfaces, food and water bowls, collars and leashes), and by people moving between infected and uninfected dogs. Dogs of any breed, age, sex or health status are at risk of infection when exposed to the virus.
The first canine influenza virus, known as H3N8 CIV, was initially identified in 2004 among racing greyhounds in Florida. Since then the virus has been documented in 41 states and is considered endemic in parts of Colorado, Florida, New York and Pennsylvania.
In 2015, a canine influenza outbreak that started in Chicago was determined to be caused by the H3N2 strain of canine influenza, a strain that previously had not been reported outside of Korea, China and Thailand. This new strain has since affected many dogs across the United States.
In early 2016, a group of cats in an Indiana shelter were infected with H3N2 canine influenza (passed to them by infected dogs), and the findings suggested that cat-to-cat transmission is possible. More research needs to be conducted to determine the risks of canine influenza to cats.
What are the Symptoms of Canine Influenza?
Canine influenza infection resembles canine infectious tracheobronchitis (“kennel cough”). The illness may be mild or severe, and infected dogs develop a persistent cough and may develop a thick nasal discharge and fever (often 104-105oF). Other signs can include lethargy, eye discharge, and reduced appetite. Some dogs may not show signs of illness, but can shed the virus and infect other dogs.
Most dogs recover within 2-3 weeks. However, secondary bacterial infections can develop and may cause more severe illness and pneumonia. Anyone with concerns about their pet’s health, or whose pet is showing signs of canine influenza, should contact their veterinarian.
Cats infected with H3N2 canine influenza show symptoms of upper respiratory illness, including a runny nose, congestion, malaise, lip smacking, and excessive salivation.
How Is the Disease Transmitted?
Dogs are most contagious during the two- to four-day incubation period for the virus, when they are infected and shedding the virus in their nasal secretions but are not showing signs of illness. Almost all dogs exposed to CIV will become infected and the majority (80%) of infected dogs develop flu-like illness.
Will Canine Influenza Spread into Canada and What Can We Do About It?
The short answer is who knows? It’s always hard to predict what will happen with influenza viruses. The spread of the H3N8 canine flu virus has been slow and sporadic and has yet to establish itself in Canada. This new H3N2 strain is more concerning because it seems to be more transmissible, and the Midwest US outbreak is unlike what has been seen in the past with H3N8.
The Best Prevention is Infection Control:
Most cases of coughing and respiratory illness that are diagnosed at Amherst are due to the kennel cough complex. The infectious agents causing this are equally contagious so the same control measures should be taken anytime your dog is shows signs of sudden respiratory illness.
- If your dog is sick, keep it away from other dogs. Influenza viruses are only shed for a short period of time, so keeping sick dogs away from other dogs for 7-14 days will help. If your dog has been exposed to dogs that might have been infected, keep it away from other dogs. It doesn’t matter if your dog is healthy. Peak flu shedding can occur very early in disease, and a lot of virus can be shed in the 24 hours before the dog starts to show signs of illness. So, keeping exposed animals away from others for 7-14 days after exposure is also a good idea, just in case.
- Don’t travel to an endemic region with your dog. If you are going on a trip to Chicago or other area where H3N2 is active and you don’t need to bring your dog along, then don’t risk exposing your dog, and/or possibly bringing the virus home with it.
- Don’t travel out of an endemic region with your dog. Likewise, if you live in an area where H3N2 is active, don’t take your dog on a trip anywhere else. If it was infected before leaving, it could take the virus to a new region.
- Don’t import dogs from shelters, puppy mills or similar facilities in areas where H3N2 is active. Animals from these facilities are at higher risk for carrying many diseases, now including canine flu.
There are vaccines against the H3N8 and H3N2 strain of canine influenza for dogs but currently none licensed for cats and only the H3N8 strain is currently available in Canada. It is not known at this time if vaccination with the H3N8 strain will provide protection against the H3N2 strain.
The influenza vaccine is a “lifestyle” vaccination, recommended for dogs at risk of exposure due to their increased exposure to other dogs – dogs that are frequently or regularly exposed to other dogs – for example at boarding or day care facilities, dog parks, grooming salons, or social events with other dogs present – are at greater risk of coming into contact with the virus. Also, as with other infectious diseases, extra precautions may be needed with puppies, elderly or pregnant dogs, and dogs that are immunocompromised.
Currently, the best prevention is to avoid taking your dog to endemic areas in the United States. Please check with the local state veterinary association before you travel with your pet.
At Amherst Veterinary Hospital we continually try to stay up to date with emerging diseases and its risk to our local pet population. If you have questions about your pet’s health please do not hesitate to ask us!
Dr. Loretta Yuen