Canine Flu Virus
(from a veterinary alert issued August 12, 2005)
SITUATION: University of Florida researchers report that
outbreaks of canine influenza virus, which causes an acute respiratory infection,
have been identified in dogs in shelters, humane societies, boarding facilities
and veterinary clinics in the SE and Eastern U.S. Recently, submitted samples
confirm the virus is present in other states. This highly contagious virus
is a newly emerging respiratory pathogen in dogs and causes a clinical syndrome
that mimics “kennel cough.” Canine influenza virus infections
are frequently mistaken for infections due to the Bordetella bronchiseptica/
parainfluenza virus complex .
CLINICAL SIGNS: Because this is a newly emerging pathogen,
all dogs, regardless of breed or age, are susceptible to infection and have
no naturally acquired or vaccine-induced immunity. Virtually 100 percent of
exposed dogs become infected. Nearly 80 percent have clinical signs. There
are two general clinical syndromes – the milder syndrome and a more
severe pneumonia syndrome. The milder disease syndrome occurs in most dogs.
In the milder disease, the most common clinical sign is a cough that persists
for 10 to 21 days despite therapy with antibiotics and cough suppressants.
Most dogs have a soft, moist cough, while others have a dry cough similar
to that induced by Bordetella bronchiseptica/ parainfluenza virus infection.
Many dogs have purulent nasal discharge and a low-grade fever. The nasal discharge
likely represents a secondary bacterial infection that quickly resolves with
treatment with a broad-spectrum, bactericidal antibiotic.
Some dogs develop a more severe disease with clinical signs of pneumonia,
such as a high fever (104 0 F to 106 0 F) and increased respiratory rate and
effort. Thoracic radiographs may show consolidation of lung lobes. Dogs with
pneumonia often have a secondary bacterial infection and have responded best
to a combination of broad-spectrum, bactericidal antibiotics and maintenance
of hydration with intravenous fluid therapy.
FATALITY RATE: Fatal cases of pneumonia have been documented,
but the fatality rate so far is low.
INCUBATION/SHEDDING PERIOD: The incubation period is two
to five days after exposure before clinical signs appear. Infected dogs may
shed virus for seven to 10 days from the initial day of clinical signs. Nearly
20 percent of infected dogs will not display clinical signs and become the
silent shedders and spreaders of the infection.
DIAGNOSIS: There is no rapid, real-time test for diagnosis
of dogs with an acute influenza virus infection. Special samples must be collected
by a veterinarian and submitted to specialized veterinary laboratories.
PREVENTION: There is no vaccine for canine influenza virus
at this time. This virus is spread by aerosolized respiratory secretions,
contaminated inanimate objects and even by people moving back and forth between
infected and uninfected dogs. This is an enveloped virus that is most likely
killed by routine disinfectants, such as quaternary ammoniums and 10 percent
bleach. Because the virus is highly contagious and all dogs are susceptible
to infection, veterinarians, boarding facilities, shelters and pet stores
should use isolation protocols for dogs that have a “kennel cough.”
It is also highly recommended that all dog owners be careful about taking their dogs to places where there are many dogs from various households and little or no routine disinfection practices employed. Persons who intend to board their dog/s should be certain to keep their dogs away from dog parks, grooming shops, dog shows etc., for two weeks prior to boarding. Dogs who have shown symptoms such as described above should NOT be boarded. Any dog that shows signs of illness on presentation for boarding will not be accepted.
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