Canine Influenza (Dog Flu) Frequently Asked Questions
What is dog flu?
Dog flu is a contagious respiratory disease. It is caused by two specific Type A canine influenza viruses (CIVs): H3N8 and H3N2. H3N2 is the CIV strain identified in the outbreak of respiratory illness of dogs in 2015.
I’ve been hearing a lot about a new strain of CIV. What does that mean?
The “new” CIV, H3N2, was identified in South Korea in 2006 and has been reported in several Asian countries. It was first identified in dogs in the U.S. in early 2015.
The first dog flu vaccine introduced in the U.S. helps protect dogs against the CIV H3N8. CIV H3N8 was first identified in dogs in the U.S. in 2004.
What are the symptoms of dog flu?
As with flu in humans, symptoms and symptom severity may vary from dog to dog. Symptoms of CIV H3N2 are similar to those of CIV H3N8. They may include reduced appetite, high fever, cough, runny nose and lethargy. Symptoms can persist for several weeks.
Dogs with CIV H3N2 may show more severe signs than dogs with CIV H3N8—or they may show no signs at all. Only diagnostic testing can distinguish which type is present.
CIV can be difficult to diagnose and potentially difficult to treat. Clinical signs—including coughing, sneezing, nasal and ocular discharge, and anorexia—sometimes don’t emerge until after the majority of virus shedding has occurred. Plus, samples collected during clinical exam may not identify CIV.4
If you have any concerns that your dog may be showing signs of dog flu, contact your veterinarian.
Is dog flu a very serious illness?
Both CIV H3N2 and CIV H3N8 are contagious and nearly all dogs exposed to dog flu will become infected. About 80% of infected dogs will show symptoms. Severity—and the symptoms themselves—will vary from dog to dog.
Both types can be a more serious illness for certain groups of dogs, including very young, very old or immunocompromised dogs. The mortality rate for dog flu in general is less than 10%. Your veterinarian can talk with you about your pet’s individual susceptibility.
My dog has been vaccinated against CIV H3N8. Does that vaccine also help protect against CIV H3N2?
At this time, it is unknown whether the current CIV H3N8 vaccine will offer cross-protection against CIV H3N2. There is a new CIV H3N2 vaccination available. This vaccination, like the CIV H3N8 vaccination, initially needs to be administered as a series of two injections, three weeks apart. There is no combination vaccination at this time for both identified types of CIV. Although flu vaccines greatly reduce the likelihood that a dog will contract flu, just like other canine respiratory vaccines they cannot eliminate the possibility of infection. Flu shots also can be ineffective against unanticipated types. For at risk dogs, considering vaccination for flu may be important to discuss with your veterinarian. It is also important to vaccinate against those respiratory illnesses (bordetella and parainfluenza, often known as “kennel cough”) which may be more common, and may often be coinfections with CIV.
How is dog flu transmitted?
Both types of dog flu can be passed from dog to dog in some of the same ways we pass flu among ourselves. Droplets from sneezing or coughing and contact with contaminated objects are the main culprits. The virus also can survive on human skin—and for at least a day on clothing—so we can transmit the virus too.
What can I do to keep my pet safe?
If there is a dog flu outbreak in your area, be aware that risk or exposure to the virus may be increased at dog parks, doggy day care centers, communal water bowls and in other settings where dogs share toys and come into close contact with each other. Wash your dog’s toys, bowls and bedding regularly. When you’ve come into contact with other dogs, wash your hands thoroughly before handling your own pet. Avoid contact with other pets, as the virus can persist on clothing and other surfaces for at least 24 hours.
What can I do to keep other pets safe?
If you are concerned that your dog may be showing signs of dog flu, contact your veterinarian and keep your dog at home. Until you’ve received examination or test results from your veterinarian, keep your dog separated from other pets. Wash your hands thoroughly after handling your own pet.
Can humans catch dog flu?
There is no evidence that CIV H3N2 or H3N8 can be transmitted to humans.
Can cats catch dog flu?
There is no evidence that CIV H3N8 can lead to clinical disease in cats. CIV H3N2 has been documented to cause infection and respiratory illness in cats.
What is canine infectious respiratory disease complex (CIRDC), and what does it have to do with dog flu?
CIRDC refers to many different bacteria and viruses that can cause respiratory disease in dogs. On the basis of symptoms alone, it generally is impossible to determine which of those pathogens is causing disease. There are vaccines that help protect against many of the pathogens that can lead to CIRDC, including dog flu.
Dog-to-dog contact or contaminated objects can spread CIRDC. Environmental factors (such as dog parks) and host-related factors (such as a dog’s overall health) also can play a part in the development of CIRDC.
What treatments are available for dog flu?
As a viral infection, dog flu cannot be cured with medication. Supportive care, such as making sure a pet is resting, eating and staying well hydrated, can help ease some symptoms and help prevent worsening of others. Sometimes antibiotics also are given to treat or guard against secondary infections. Your veterinarian can talk with you about specific treatment options for your pet’s symptoms.
Keep dogs and cats with signs of respiratory infection away from other pets until your veterinarian tells you otherwise.