Canine Influenza Virus (CIV)
Currently, two strains of CIV have been identified in the U.S. The H3N8 strain of canine influenza was first identified in 2004 in Florida. Since then, it has been found in several other states. In 2015, the H3N2 virus strain was identified as the cause of an outbreak of canine influenza in Chicago.
Canine influenza can occur year round. So far, there is no evidence that canine influenza infects people.
The symptoms of a CIV infection resemble those of canine infectious tracheobronchitis ("kennel cough"). Dogs infected with CIV 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. Canine influenza infections can cause mild to severe illness in dogs. Some infected dogs may not show any signs of illness, but can still be contagious and able to infect other dogs
Most dogs recover within 2-3 weeks. However, some dogs may develop secondary bacterial infections which may lead to 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.
Laboratory tests are available to diagnose both H3N8 and H3N2 CIV. Consult us for more information regarding testing for CIV.
Transmission and prevention of canine influenza
Dogs infected with CIV are most contagious during the two- to four- day virus incubation period, when they shed the virus in their nasal secretions but do not show signs of illness. The virus is highly contagious and almost all dogs exposed to CIV will become infected. The majority (80%) of infected dogs develop flu-like illness. The mortality (death) rate from CIV is low (less than 10%).
To reduce the spread of CIV, isolate dogs that are sick or showing signs of a respiratory illness, and isolate dogs known to have been exposed to an infected dog.
Isolate dogs infected with H3N2 canine influenza for at least 21 days. Practice good hygiene and sanitation, including hand washing and thorough cleaning of shared items and kennels, to reduce the spread of CIV. Influenza viruses do not usually survive in the environment beyond 48 hours and are inactivated or killed by commonly used disinfectants.
Vaccines are available for both the H3N8 and H3N2 strains of canine influenza virus. The CIV vaccination is a "lifestyle" vaccination, recommended for dogs at risk of exposure due to their increased exposure to other dogs – such as boarding, attending social events with dogs present, and visiting dog parks. Our office can provide you with additional information about the vaccines and whether you should consider vaccinating your dog.
What is H3N2 Canine Influenza Virus?
H3N2 canine influenza virus (H3N2 CIV) is a very contagious influenza virus that infects dogs. This virus recentlyemerged in the US in 2015. It has already infected thousands of dogs in more than 30 states. H3N2 CIV has alsoinfected cats but there is no evidence that it can infect people.
What does H3N2 CIV cause?
H3N2 CIV causes a respiratory infection in dogs that is also known as “dog flu”. Common symptoms include sneezing, nasal discharge, and frequent coughing that can last for 2 weeks or more. Many dogs have a fever, decreased appetite, and lethargy during the first few days of illness. Some dogs have more serious disease and pneumonia that requires hospital care. H3N2 CIV can cause respiratory infections in cats too. The cats startsneezing and have nasal discharge but usually do not cough.
How do dogs get H3N2 CIV infection?
H3N2 CIV is spread by direct contact with a sick dog and by contact with an environment or people that are contaminated with the virus. Coughing dogs produce invisible virus‐containing mists that travel more than 10 feet in the air, facilitating rapid spread of virus over distances. This type of virus transmission contributes to a rapid increase in coughing dogs in a kennel situation. The virus can survive in the environment (kennel surfaces, food/water bowls, collars/ leashes, toys, beds) or on people’s clothing and hands for 12 to 24 hours before it dies. It is easily killed by handwashing with soap and water, normal laundering of clothing and bedding, and washing food/water bowls and toys with soap and water.
What dogs are at risk for H3N2 CIV?
Most dogs do not have immunity to H3N2 CIV. This means that dogs of any breed, age or health status will likely be infected if they are exposed to the virus. Dogs at most risk for exposure are those with a social lifestyle and participate in group events or are housed in communal facilities, especially in communities where H3N2 CIV is circulating. This includes dogs in boarding kennels, day care centers, shelters, dog shows, veterinary clinics, pet stores, grooming parlors, etc. Dogs that mostly stay at home and walk around the neighborhood are at low risk.
What if my dog is diagnosed with H3N2 CIV?
Most dogs recover at home without any complications. The most important aspect of home care is to keep your dog isolated from all other dogs for 4 weeks. While dogs recover from illness in about 2 weeks, they can remain contagious to other dogs for up to 4 weeks. If you have other dogs or cats in the house, then all of them must be isolated in the home for 4 weeks. Your veterinarian will provide instructions on how to monitor the health of all the pets and when to call about concerns. About 20% of dogs can progress to pneumonia. Dogs with pneumonia typically have decreased appetite, are very lethargic, and may have labored breathing. Call your veterinarian if you see these signs. These dogs likely need special hospital care for recovery. Fortunately, the mortality rate for H3N2 CIV is low.
What can I do to protect my dog against H3N2 CIV?
You should also remain aware of any information about confirmed documentation of H3N2 CIV in your community or communities where you take your dog. If this virus is present in the community, then be careful about exposing your dog to events or facilities with other dogs. Knowledge and common sense are your best defenses against canine influenza. The most important step is to vaccinate your dog against the canine influenza viruses. Just like human flu vaccines, the H3N2 CIV vaccine may not completely prevent infection but will make it less likely. Additionally, if a vaccinated dog does get infected, the disease is likely to be more mild and of shorter duration. The vaccine can also protect against pneumonia.