like you to know that by the time Canine Influenza H3N8 arrives in the St. Louis area it may be too
late to protect your dog. Protection provided by the vaccine requires 2 doses administered 3 weeks apart.
Thus, KAH recommends that you have your
pet vaccinated if it has exposure to other dogs outside the home.
articles on Canine Influenza are available on the web.
This article is from the Center for Disease Control, Atlanta,
Key Facts about Canine Influenza (Dog Flu)
Questions & Answers
What is canine influenza (dog flu)?
Dog flu is a contagious respiratory disease in
dogs caused by a specific Type A influenza virus
referred to as a “canine influenza virus.” This is a
disease of dogs, not of humans.
What is a canine influenza virus?
The “canine influenza virus” is an influenza A
H3N8 influenza virus (not a human influenza virus)
that was originally an equine (horse) influenza
virus. This virus has spread to dogs and can now
spread between dogs.
How long has canine influenza been around?
The H3N8 equine influenza virus has been known to
exist in horses for more than 40 years. In 2004,
however, cases of an unknown respiratory illness in
dogs (initially greyhounds) were reported. An
investigation showed that this respiratory illness
was caused by the equine influenza A H3N8 virus.
Scientists believe that this virus jumped species
(from horses to dogs) and has now adapted to cause
illness in dogs and spread efficiently among dogs.
This is now considered a new dog-specific lineage of
H3N8. In September of 2005, this virus was
identified by experts as “a
newly emerging pathogen in the dog population”
in the United States.
What are the symptoms of this infection in dogs?
The symptoms of this illness in dogs are cough,
runny nose, and fever. However, a small proportion of
dogs can develop more severe respiratory disease.
How serious is this infection in dogs?
The number of dogs infected with this disease
that die is very small. Some dogs have asymptomatic
infections (no symptoms), while some have severe
infections. Severe illness is characterized by the
onset of pneumonia. Although this is a relatively
new cause of disease in dogs and nearly all dogs are
susceptible to infection, about 80 percent of dogs
will have a mild form of disease.
How does dog flu spread?
Canine influenza virus can be spread by direct
contact with respiratory secretions from infected
dogs, by contact with contaminated objects, and by
people moving between infected and uninfected dogs.
Therefore, dog owners whose dogs are coughing or
showing other signs of respiratory disease should
not participate in activities or bring their dogs to
facilities where other dogs can be exposed to the
virus. Clothing, equipment, surfaces, and hands
should be cleaned and disinfected after exposure to
dogs showing signs of respiratory disease.
Is there a test for canine influenza?
Testing to confirm canine influenza virus
infection is available at veterinary diagnostic
centers. The tests can be performed using
respiratory secretions collected at the time of
disease onset or using two blood samples; the first
collected while the animal is sick and the second 2
to 3 weeks later.
How is canine influenza treated?
Treatment largely consists of supportive care.
This helps the dog mount an immune response. In the
milder form of the disease, this care may include
medication to make your dog more comfortable and
fluids to ensure that your dog remains
well-hydrated. Broad spectrum antibiotics may be
prescribed by your veterinarian if a secondary
bacterial infection is suspected.
Is there a vaccine for canine influenza?
Yes, an approved vaccine is available.
What is the risk to humans from this virus?
To date, there is no evidence of transmission of
canine influenza virus from dogs to people and there
has not been a single reported case of human
infection with the canine influenza virus. While
this virus infects dogs and spreads between dogs,
there is no evidence that this virus infects humans.
However, human infections with new influenza
viruses (against which the human population has
little immunity) would be concerning if they
occurred. Influenza viruses are constantly changing
and it is possible for a virus to change so that it
could infect humans and spread easily between
humans. Such a virus could represent a pandemic
influenza threat. For this reason, CDC and its
partners are monitoring the H3N8 influenza virus (as
well as other animal influenza viruses) along with
instances of possible human exposure to these
viruses very closely. In general, however, canine
influenza viruses are considered to pose a low
threat to humans. As mentioned earlier, while these
viruses are well established in horse and dog
populations, there is no evidence of infection among
humans with this virus.
My dog has a cough what should I do?
Schedule an appointment with your veterinarian so
that they can evaluate your dog and recommend an
appropriate course of treatment.
Where can I find more information on canine
More information on canine influenza in pet dogs
can be found in this article:
Influenza A Virus (H3N8) in Dogs with Respiratory
Disease, Florida in Emerging Infectious Diseases
University of Florida College of Veterinary
Medicine in Gainesville
10 Things to Know About the H3N8 Dog Flu
Cynda Crawford, D.V.M., Ph.D.
Albert for The New York Times Who’s at risk from
Dr. Cynda Crawford, clinical assistant professor in the Maddie’s Shelter
Medicine Program at the University of Florida College of Veterinary Medicine in
Gainesville, recently answered dozens of readers’ questions on the
Consults blog, “The Dog Flu Virus: Are You or Your Pet At Risk?” Many
readers had questions about flu symptoms, how the virus is spread and whether
their pets should receive the newly approved vaccine for the disease. Here are
10 things Dr. Crawford believes everyone should know about canine influenza and
the risks to pets and people.
What is canine influenza?
Canine influenza is a highly contagious respiratory infection of dogs caused
by a novel influenza virus that was first discovered in 2004. We do not use the
general term “dog flu” because it could refer to any flu-like illness in dogs
due to various causes. Rather, canine influenza is a specific disease caused by
a particular subtype, H3N8, of the influenza A virus.
Where does canine influenza occur?
Canine influenza has been documented in 30 states and the District of
Columbia. At this time, the canine influenza virus is very prevalent in many
communities in Colorado, Florida, New York and Pennsylvania. There is no
evidence that canine influenza H3N8 is currently infecting dogs in other
What type of infection does canine influenza virus cause?
Like influenza viruses that infect other mammals, canine influenza virus
causes an acute respiratory infection in dogs. It is one of several viruses and
bacteria that are associated with canine infectious respiratory disease, or
what’s commonly referred to as “kennel cough.” The canine influenza virus can
cause respiratory disease by itself or along with other canine respiratory
Unlike human influenza, canine influenza is not a “seasonal” infection.
Infections can occur year round.
What are the symptoms and clinical signs of canine influenza?
Like influenza viruses in other species, canine influenza virus causes a
flu-like illness consisting of cough, sneezing and nasal discharge (”runny
nose”). Fever can also occur, but it is usually transient and rarely noticed by
pet owners. There are no clinical signs that distinguish canine influenza from
other respiratory infections. That is why diagnostic tests must be performed to
determine the cause of respiratory infections in dogs (see below).
Virtually all dogs exposed to the canine influenza virus become infected;
about 80 percent develop a flu-like illness, while another 20 percent do not
become ill. Fortunately, most dogs recover within two weeks without any further
health complications. However, some dogs progress to pneumonia, which is usually
due to secondary bacterial infections.
While the death rate for canine influenza is very low, the secondary
pneumonia can be life-threatening in some cases. There is no evidence that dogs
of particular age or breed are more susceptible to developing pneumonia from
Who is susceptible to canine influenza?
Because canine influenza is due to a virus that is novel to the canine
population, dogs lack preexisting immunity to the virus. Dogs of any breed, age
or vaccination status are therefore susceptible to infection. It is likely that
dogs that have recovered from infection retain immunity to re-infection for an
undetermined time period, although studies have not verified for how long.
Canine influenza is most likely to spread in facilities where dogs are housed
together and where there is a high turnover of dogs in and out of the facility.
Dogs in shelters, boarding and training facilities, day care centers, veterinary
clinics, pet stores and grooming parlors are at highest risk for exposure to the
virus, especially if these facilities are located in communities where the virus
is prevalent. Dogs that mostly stay at home and walk around the neighborhood are
at low risk.
Canine influenza virus does not infect people, and there is no documentation
that cats have become infected by exposure to dogs with canine influenza. Nor is
there any evidence that the canine virus can infect birds.
How is canine influenza transmitted?
As with other respiratory pathogens, the most efficient transmission occurs
by direct contact with infected dogs and by aerosols generated by coughing and
sneezing. The virus can also contaminate kennel surfaces, food and water bowls,
collars and leashes, and the hands and clothing of people who handle infected
dogs. Fortunately, the virus is easily inactivated by washing hands, clothes and
other items with soap and water.
How is canine influenza treated?
Since canine influenza is a viral infection, treatment consists mainly of
supportive care while the virus runs its course, much like for human influenza.
Dog owners should consult with their veterinarians if they think their dog has
canine influenza. The veterinarian can determine what type of supportive care is
needed, including whether antibiotics should be given for secondary bacterial
infections. Dogs with pneumonia most likely require more intensive care provided
in a hospital setting under the supervision of a veterinarian.
Is canine influenza contagious?
Like influenza infections in other species, canine influenza is highly
contagious. Infected dogs shed virus in their respiratory secretions for 7 to 10
days, during which time the dog is contagious to other dogs. Infected dogs that
do not show clinical signs are also contagious.
Once the virus has run its course, the dog is no longer contagious.
Therefore, we recommend that dogs with canine influenza be isolated from other
dogs for two weeks to err on the conservative side. The canine influenze virus
does not cause a permanent infection.
How is canine influenza diagnosed?
Canine influenza cannot be diagnosed by clinical signs because all of the
other respiratory pathogens cause similar signs of coughing, sneezing and nasal
discharge. For dogs that have been ill for less than four days, veterinarians
can collect swabs from the nose or throat and submit them to a diagnostic
laboratory that offers a validated PCR test for canine influenza virus. The most
accurate test recommended for confirmation of infection requires the collection
of a small blood sample from the dog during the first week of illness, followed
by collection of another sample 10 to 14 days later. The paired serum samples
are submitted to a diagnostic laboratory for measurement of antibodies to CIV
that were formed in response to infection.
Is there a vaccine for canine influenza?
In May 2009, the United States Department of Agriculture approved for
licensure the first influenza vaccine for dogs. The vaccine was developed by
Intervet/Schering Plough Animal Health Corporation.
The canine influenza vaccine contains inactivated whole virus, so there is no
chance that the vaccine itself can cause respiratory infections. During tests to
evaluate vaccine performance, there were no side effects or safety issues in a
field trial that included more than 700 dogs ranging in age from six weeks to 10
years and representing 30 breeds.
The vaccine is intended as an aid in the control of disease associated with
C.I.V. infection. Although the vaccine may not prevent infection, efficacy
trials have shown that vaccination significantly reduces the severity and
duration of clinical illness, including the incidence and severity of damage to
the lungs. In addition, the vaccine reduces the amount of virus shed and
shortens the shedding interval. This means that vaccinated dogs that become
infected are less likely to have severe symptoms and are not as contagious to
other dogs. These benefits are similar to those provided by influenza vaccines
used in other species, including people.
The canine influenza vaccine is a “lifestyle” vaccine in that it is intended
for dogs at risk for exposure to C.I.V., including those that participate in
activities with many other dogs or those housed in communal facilities,
particularly in communities where the virus is prevalent. Dogs that may benefit
from canine influenza vaccination include those that are already receiving the
kennel cough vaccine for Bordetella because the risk groups are the same.
Dog owners should consult with their veterinarian to determine whether their
dog’s lifestyle includes risk for exposure to C.I.V., and the protection
provided by the canine influenza vaccine. The vaccine is not yet available in
veterinarians’ offices, and the price has not yet been set.
From the Manufactures of the Vaccine: