Canine Influenza Update
January 2016
As many know, this past year the Chicagoland area was ground zero for an outbreak of canine
influenza virus (CIV). Prior to 2015, the only form of canine influenza identified in the US was H3:N8, a
relative of Equine Flu that was first identified at dog tracks in 2004. However, shortly after the
emergence of this outbreak, it was discovered that the virus responsible for the current epidemic was
actually a relative of Asian bird flu, H3:N2. Since that time, much has been learned about the new
strain of CIV and how it affects our pet. In an effort to keep our clients as up to date as possible, we
have compiled the latest information below. If you have additional questions or concerns, please
contact our office and speak to one of our doctors.
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Respiratory diseases in dogs are most often caused by parainfluenza, Bordetella and
adenovirus, all of which are routinely vaccinated against.
The recent respiratory disease outbreak in Chicago in Spring 2015 was caused by the newly
identified influenza virus H3: N2.
There are two distinct strains of canine influenza virus identified: H3:N2 and H3:N8.
These respiratory viruses are most often transmitted through direct or indirect contact in social
settings such as doggie daycares, boarding kennels, dog parks, grooming facilities, training
facilities, hospitals and common areas in apartment complexes such as elevators and stairwells.
Incubation period (the time between contact with the virus and onset of symptoms) is 2-4 days,
while virus shedding (contagiousness) can persist for 3-3.5 weeks. Respiratory symptoms of
coughing, sneezing, nasal discharge and fever can persist for 2-4 weeks, or longer.
Two distinct vaccines are available. Owners of highly social dogs should discuss these vaccines
with their veterinarian to decide if one or both vaccinations are warranted.
Danada Veterinary Hospital does not require either influenza vaccine at this time.
What are the clinical signs of CIV and are some dogs immune?
Symptoms of both H3:N8 and H3:N2 influenza include mucoid eye and/or nasal discharge, moderate to
severe cough, lethargy, loss of appetite, and moderate to severe fever. These signs usually develop 2-4
days after exposure. Secondary bacterial pneumonia is very common in both cases. While the infection
can be fatal in some, fortunately the death rate from CIV is low.
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Canine Influenza Update
January 2016
There appears to be no breed or age predilections for CIV infection so all dogs are susceptible. Dogs
that contract the disease and recover can develop short-lived immunity to the disease, but it is
unknown how long this immunity will last.
How do dogs contract the CIV virus?
Like the H3:N8 virus, H3:N2 is spread from dog to dog via inhalation of airborne virus particles from
coughing and sneezing dogs. Environments contaminated with infected saliva, phlegm, nasal or eye
discharge are also sources of infection. Clothing and items such as toys and food/water bowls are the
most common indirect sources of infection.
The majority of infections occur in highly social environments such as boarding kennels, day cares, and
training classes. Facilities that see a high volume of dog traffic such as vet clinics, pet stores, groomers,
and even apartment buildings with common areas (stairwells and elevators) are also potential sources.
Outdoor environments are less likely to be sources of infection as sunlight, heat, and cold can affect
the virus’ viability. However, virus survival in the environment is highly dependent on weather
conditions.
How contagious is the new strain of CIV?
Both forms of CIV are highly contagious. Airborne virus can spread out many feet from an infected dog,
and can linger for days if not disinfected well. H3:N2 appears much more contagious than H3:N8 virus
and therefore spreads easier and faster. H3:N2 also lingers longer in infected individuals. While the
H3:N8 virus usually sheds from infected pets for 7-10 days, the new strain has been isolated in dogs for
as long as 3-3.5 weeks after infection.
Can people or cats get CIV?
As of now, no cases of CIV H3:N2 or H3:N8 have been reported in the US in species other than dogs.
However, cats or human exposed to an infected dog can serve as a source of infection for any other
dogs that they contact.
Is CIV just a Chicago Issue?
So far, outbreaks have occurred in many different parts of the country. The largest outbreaks appear to
be closely related to high volume boarding times (Spring Break in Chicago, Memorial Day in Atlanta,
Fourth of July in North Carolina, and Thanksgiving in Texas). Chicago saw most of our infections in the
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Canine Influenza Update
January 2016
spring, but we have had slight increases in the number of positive cases reported in June, July, and
most recently in December confirming that the virus is still around in the Midwest.
What should you do if you think your dog has been infected?
Clients with coughing dogs should call us immediately so that we can direct them. Many patients can
be treated at home if signs are caught early. Even if your pet is having trouble breathing, your phone
call allows us to get the hospital prepared for your arrival.
Testing can be performed by a variety of labs to confirm the presence of CIV or a number of other
respiratory viruses. Thanks to a guarantee from our vaccine provider, any pet who has received
Bordetella, CIV, or Parainfluenza vaccine and develops respiratory signs can have this testing done at
no charge to you. Testing is time sensitive and should be performed within the first 5 days of clinical
signs whenever possible.
Keep any animals that develop CIV signs away from other dogs for at least 4 weeks. Do not walk them
around the neighborhood or socialize them in any way. Virus shedding should not go on longer than
3.5 weeks even though inflammatory changes in the lungs may allow the cough to linger. If planning to
return to daycare or training classes, a CIV test can be run to confirm no virus is being shed prior to
returning to these facilities.
Use good hygiene. Routine hand washing with soap and water will kill the virus on human skin, water
bowls, toys, etc. Hand sanitizer works well so long as secretions (Phlegm, saliva, nasal discharge) are
not present. If secretions are present they need to be removed with soap and water before applying
sanitizer. Clothing should be changed after contacting an infected dog whenever possible.
What is Danada doing to prevent the spread of infection?
At Danada Veterinary Hospital, we treat all respiratory patients as potentially contagious. We instruct
clients to leave their pets in their vehicle when they arrive and we screen the pets outdoors before
allowing them in the building. If a patient is admitted into the building, they are placed immediately in
a pre-designated exam room and remain there until their appointment is over.
CIV, like most respiratory viruses, is very effectively controlled with proper cleaning. Following an
appointment in which we treat a contagious respiratory pathogen, the entire room is disinfected, and
no other dogs are allowed in that room for 24 hours. We use dedicated stethoscopes, thermometers,
and other equipment for these cases that do not get used on other patients. Doctors and staff that
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Canine Influenza Update
January 2016
handle these patients change lab coats and scrubs to prevent contamination on clothing. All surfaces
that are contacted by an infected pet, the doctor, or the client are disinfected immediately including
doorknobs, hallways, benches, etc.
What can pet owners do to minimize their pet’s risk?
The best protection is to avoid high risk environments whenever possible. The highest risk
environments are daycares, boarding facilities, and training facilities that allow constant dog-to-dog
interaction. These places can be extremely difficult to disinfect and a single infected animal can
contaminate the entire facility. Peak boarding times such as Spring Break, holidays, and the summer
vacation season, are perhaps the most at-risk times for infection. If you do need to board your dog,
choose a facility that does not allow much dog-to-dog interaction to limit exposure risks. Alternatively,
we recommend leaving your pet with a friend or hiring an at-home pet sitter if possible.
Keep your dog vaccinated against the most common respiratory pathogens. This includes Bordetella,
Adenovirus, and Parainfluenza (Note that Adenovirus and Parainfluenza are viruses found in our
distemper vaccine). CIV is only one part of a complex group of viruses and bacteria that can cause
respiratory disease in dogs. While vaccinating against these diseases does not completely prevent
upper respiratory illness, it does limit the severity of infections. Vaccines also limit the contagiousness
of the illnesses by decreasing the shedding of virus from an affected individual. Lastly, vaccines lower
the risk of the secondary infections in the event that your dog is exposed to more aggressive infections
like influenza.
For these reasons, vaccinations for Bordetella, Adenovirus, and Parainfluenza are required for all
patients that stay in our facility for boarding or elective procedures. Although some local facilities do
not have the same vaccine requirement that we enforce, we strongly encourage clients using these
businesses to keep their pets vaccinated. If you are not required to vaccinate, no one else using that
facility is required either. This leaves your dog more vulnerable to exposure.
Are there CIV vaccines and should dogs get them?
At the time of the initial outbreak, No FDA approved vaccination existed for H3:N2. The hope at first
was that the FDA approved H3:N8 vaccine, available since 2006, would provide adequate crossprotection against both strains of CIV. By June the sequencing of the new virus revealed that the two
strains were too different to expect reliable cross-protection from the H3:N8 vaccine.
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Canine Influenza Update
January 2016
In late November, two companies released H3:N2 vaccines under conditional FDA licensing. These
vaccines do not yet have complete FDA approval, but they have been shown to be both safe and
effective in the small clinical trials. The FDA allowed expedited vaccine development due to the
epidemic nature of the H3:N2 outbreak nationwide. However, in our immediate area, the number of
cases over the last 6 months is low. As such, our opinion is that we would like to see more clinical data
on the vaccine prior to recommending widespread use. The H3:N2 vaccine is available through our
office if you feel your dog needs it or if your dog goes to facilities that require it.
H3:N8 vaccine has long been shown to effectively prevent and limit the severity of the older strain of
CIV. However, we have yet to see H3:N8 as a major source of infection in the Wheaton area. Therefore,
we do not currently encourage H3:N8 CIV vaccine for all patients. As with the H3:N2 vaccine, we do
offer it to clients who request it, or to those whose dogs use facilities that require it.
Please do not hesitate to contact us if you have questions or would like to discuss what is best for your
pet’s health.
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