Canine Influenza

written by Linda Aronson, DVM

Despite all the panic in the presses,
canine influenza is not the threat
we’ve been led to believe. This is not
bird flu. Still, we need to inform ourselves
of the facts so we can be prepared
in case our dogs get sick.
Canine influenza is a viral disease
and it is thought to be a mutation of
the virus that causes equine influenza.
Actually, this also is a group of
viruses. Dogs should never be vaccinated
with products intended for
the control of equine flu.
Two clinical forms have been reported
in dogs. The mild form resembles
kennel cough caused by the
Bor d a te l l a bron c hi s ep t i c a/
parainfluenza virus complex. Dogs
may have a dry cough - like kennel
cough - or a soft moist cough. This
form lasts for 10 to 30 days. There
may also be a thick, often green, nasal
discharge as a result of secondary
bacterial infection. Dogs with the
severe form have high fevers (104 to
106oF) and clinical signs of pneumonia
(possibly due to secondary bacterial
infection). Because this is a new
disease virtually all dogs will be susceptible
to infection, and about 80%
of exposed dogs will show signs of
illness; most though have the mild
form. About 5 to 8% of the dogs developing
pneumonia have died.
The disease was first seen among
racing greyhounds at a Florida track
in January 2004, from there it spread
to other tracks, and finally to pet
dogs, at first in pet shelters, humane
societies, pet stores, breeding kennels
and finally in the general pet
population. To check to see if canine
influenza has been reported in your
state go to the Cornell Veterinary Diagnostic
Laboratory site http://
www.diaglab.vet.cornell.edu/issues/
civ-stat.asp
Treatment for canine influenza is
largely supportive. If your dog develops
a nasal discharge and/or pneumonia
he should receive a broad
spectrum antibiotic. Dogs with the
severe form or any that are dehydrated
should receive intravenous
fluids too. Because dogs catch the
virus from other dogs avoiding sick
dogs is the best prevention. Boarding
kennels and other places where dogs
are in close proximity should be carefully
monitored, and steer clear of sick
dogs. If you plan to leave your dog at
a kennel, ask if there are plans in
place to isolate any dogs that become
sick, and what action the kennel
would take should there be an outbreak.
The virus can also be passed
by respiratory secretions and contaminated
objects. Clothing, equipment,
surfaces and hands must be
cleaned and disinfected after exposure
to any dog showing signs of respiratory
illness – laundering is sufficient
for clothing.
Manufacturers are trying to produce
a vaccine against canine influenza. If
your dog is to be exposed to other
potentially infected dogs, some are
recommending vaccinating against
Bordatella bronchiseptica, parainfluenza
and adenovirus type 2, both to
prevent secondary superinfection of
dogs with canine influenza with these
diseases, and to make it easier to
rule out these diseases as the cause
of infection in sick dogs. However,
some dogs do develop kennel cough
subsequent to vaccination.
There is no rapid test for canine
influenza so care must be taken to
prevent the spread of all respiratory
diseases while test results are pending.
Antibodies to the virus do not
appear in the serum until 7 or more
days after the onset of clinical signs
(acute phase). Convalescent samples
can be collected 2 weeks later to
show that the infection is being
cleared. Post-mortem analysis of
fresh lung and tracheal tissue can
prove the cause of the pneumonia,
and Cornell is working on improving
viral detection in respiratory secretion
samples of live dogs.
At this time, it does not seem that
canine influenza can be spread to
other animals (even horses) or humans.
However, viruses do mutate,
and handling these dogs carefully,
not eating in their presence, etc is
recommended even when there are
no other dogs present.
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A grateful thank you to Linda Aronson, DVM for the use of this article.