By Eileen Alberton, DVN

Canine Influenza is a relatively new disease in dogs, caused by the Canine Influenza Virus, or CIV.  Because it is new, most of the dog population has not been exposed to it, and has no immunity to it. 

Research shows that if a group of dogs is infected, 10-20% will show no symptoms, and of the 80-90% that do get sick, only 20% will be very ill.

Flu viruses tend to be species specific, in other words, dog flu affects dogs, people flu affects people; but these viruses can also mutate easily, and good hygiene is always encouraged after handling an infected animal.  In the case of CIV, researchers believe, because of similarities between the equine and canine subtype, that this virus jumped from horses to greyhounds at racing facilities in Florida in 2003.  Since then it has spread from there throughought many states, and now is being seen in some areas of the northwest.  Hot spots still tend to be Florida, New York, New Jersey, Pennsylvania and Colorado.                                                                                                                    

Dogs of any breed or age can be affected.   Symptoms are similar to those caused by any of the agents that cause canine infectious respiratory diseases: viruses (CIV, parainfluenza, distemper, adenovirus, coronavirus, herpesvirus), and bacteria (bordatella, mycoplasma and streptococcus). Symptoms range from mild cough, low grade fever, and runny nose, to productive cough that lasts up to 30 days, thick, pussy or bloody nasal discharge and very severe pneumonia.  Even if the dog shows no symptoms, he can still be a carrier of the disease.  

Transmission of the CIV is due to droplets that are aerosolized from coughing and sneezing, from direct contact with respiratory secretions of an infected dog, or indirectly from clothing, dishes, blankets, hands, shoes, and even doorknobs. The virus seems to stay airborne for a long time, being able to spread up to 20 feet, compared to upper respiratory disease in cats that can only travel 4 feet.  It can also survive for hours in dried mucus.

Like with any other viral infection, there is no specific treatment for CIV infection. A mild case may not need to be treated at all, and may be misdiagnosed as kennel cough or one of the other respiratory diseases. Sick animals may need to be hospitalized, given intravenous fluids to maintain hydration, feeding tubes if not eating, kept warm, and put in an oxygen tent if needed. Antibiotics are given to treat secondary bacterial infection.  Your veterinarian may recommend blood work, chest x-rays, and sample collection for cultures to identify actual causative agents and plan a treatment protocol. Dogs with very severe illness, and complicated pneumonia, may die, or have to be euthanized. 

Confirming the CIV virus may be especially useful in kennel or shelter situations to help decide on protocols to minimize spread, but timing for testing is very important.  Different tests are only reliable during certain times of the infection.  Also complicating a definite diagnosis is that there are many other agents, as seen above, that have similar symptoms, and these can co-exist with CIV.  At this time, there is no definitive test that can be done easily in a clinic. 

There is a vaccine available, and though it is not considered one of the 'core vaccines', there is a sector of dogs whose lifestyle makes them at higher risk for exposure.  High risk dogs include those that go frequently to dog parks, day cares, groomers, kennels, dog shows and trials, or those that travel frequently.  Stay at home dogs are not high risk! Also at higher risk are dogs that are very young, very old, or immune-compromised.    

As with many vaccines for upper respiratory infections, the vaccine may not prevent contracting the infection, but symptoms are less severe, and shedding of the virus (transmission) is also less.  Discuss with your veterinarian if you think your dog is at risk.

In summary, for now, most dogs in our area are not high risk. Those that are, if infected, will not get seriously ill, or will recover with supportive care. If you have been somewhere where you think your dog may have been exposed to CIV, or any other contagious disease, remember to alert the receptionist when you make your vet appointment, so that proper isolation protocol can be followed when you arrive at the hospital.  And keep your dog away from other dogs until it has fully recovered!