Influenza viruses of an assortment of varieties have been the subject of concern for humans, wildlife, and domestic animals for many decades. Dogs were largely felt to be exempt from “the flu” until 2004 when a new canine influenza virus, clearly stemming from the equine influenza virus, was isolated from several groups of Florida racing greyhounds. The problem seemed confined to the racing industry until 2005 when cases involving pet dogs began appearing in boarding facilities.
In the last weeks of September 2005 and continuing into October, numerous warnings to dog owners about a new lethal canine disease swept the Internet. Some of these warnings contained legitimate information while others contained half-truths or information that was simply wrong. Let’s sort out the facts from the theories from the misinformation.
Here is an FAQ regarding this relatively new virus that has come to be considered part of the kennel cough complex.
What is Canine Influenza?
|
 |
| Group of influenza viruses |
|
Let’s start with what an influenza virus is. Influenza viruses represent a specific type of virus. There are actually three types (genera) of influenza viruses: type A (including the canine influenza virus), type B, and the less closely related type C. They produce fever, joint pain, and respiratory signs with which we are all familiar. Death is unusual but stems from respiratory complications and is most common in the very old and very young.
On its surface the virus has an assortment of proteins that determine its strain or subtype, and it is against these surface proteins that our bodies mount an immune response. If a viral strain mutates and sufficiently changes its surface proteins, a new strain is created. A new strain is one where the susceptible population has no immunity and infection can spread rapidly.
Unless a mutation occurs as described, influenza virus strains are specific to host species. Human influenza only infects humans. Equine influenza only infects horses. Canine influenza only infects dogs.
Molecular studies indicate that canine influenza represents a mutation from the equine influenza virus. Canine influenza was first confirmed in a racing greyhound in 2004 and has largely been a concern of the racing greyhound industry, particularly in Florida.
Starting in April 2005, the canine influenza virus has been seen in pet populations of many states besides Florida.
What Happens to the Sick Dogs?
Infection rate is high (depending on which report one reads) but 20-50% will simply make antibodies and clear the infection without any signs of illness at all.
The other 50-80% will get symptoms of the “flu:” they will have fevers, listlessness, coughing, and a snotty nose. Most dogs will recover with supportive treatment (antibiotics, perhaps nebulization/humidification, etc.). A small percentage of dogs will get pneumonia. These dogs are at risk for death, and support becomes more aggressive: hospitalization, intravenous fluid therapy, etc. Most of these dogs will recover as long as they receive proper care. Mortality rate is 5-8%
The incubation period is 2 to 5 days and the course of infection lasts 2 to 4 weeks. Because this is an emerging disease, few dogs will have immunity to it and there is currently no vaccine. This means that any dog is a candidate for infection.
The point is not to ignore a coughing dog.
Do not allow your dog to socialize with coughing dogs. If your dog develops a cough, see your veterinarian.
If your dog develops a snotty nose, listlessness, and a cough don’t be surprised if your veterinarian wants to look at chest radiographs and considers hospitalization.
How is the Disease Transmitted?
Dogs that are infected will shed virus in body secretions whether or not they appear to be sick. Virus transmission can occur from direct contact with an infected dog or with its secretions. Kennel workers have been known to accidentally bring the virus home to their own pets. The virus persists on toys, bowls, collars, leashes etc.
How are Sick Dogs Treated?
Fevers are treated with anti-pyretic medications or cool water baths. Pneumonia results from secondary bacterial infections (i.e. bacteria invading the lung after the virus has damaged the tissue and compromised its ability to defend itself). Pneumonia in dogs is virtually always secondary in this way, meaning that an initial condition damages the lung and allows bacterial invaders to settle in, and treatment is similar regardless of the cause.
One treatment that might be different in this disease versus other pneumonias or respiratory diseases is oseltamivir (Tamiflu). This is an antiviral medication used in treating human influenza and it is helpful only if used early in the course of infection or in prevention of infection in exposed dogs. For more details on this medication click here.
Can Dogs get Reinfected?
After a dog has recovered from canine influenza, immunity appears to last at least 2 years.
How are Dogs Tested for Canine Influenza?
In a perfect world there would be a simple test that could be performed on a single sample and yield unequivocal results, but there are two main ways to confirm canine influenza infection.
PCR Testing
PCR testing is a method of testing involving amplifying small samples of DNA to make them more easily detectable. A nasal swab is used for the sample but timing is crucial; the sample must be obtained 3 to 4 days after the onset of symptoms. Because timing is difficult, this method is not commonly recommended.
Serology
Here, a blood sample is tested for antibodies against canine influenza virus and the antibody level is compared to that from a second sample taken later. The first sample is drawn within one week of the onset of symptoms and the second sample is drawn 2 to 3 weeks later. If the second sample shows a four-fold increase in antibody level, this indicates a true infection has occurred. This inconveniently means that diagnosis cannot be confirmed for several weeks after the dog has gotten sick. A single sample with antibodies only indicates that the dog has been exposed to influenza and does not clarify whether the infection is current, recent or in the long past.
Negative test results are not felt to rule out a diagnosis of canine influenza infection.
Does Vaccination against Kennel Cough (Bordetella) or Parainfluenza offer any Protection against Canine Influenza?
No. These are all completely different infections; however, work on the development of a canine influenza vaccine is underway.
Can People Get Infected?
People cannot get infected by this virus. Influenza viruses are specific for their host species and require a dramatic mutation in order to jump species. One should not be concerned about getting an influenza infection from a dog, horse, or any other species other than a fellow human being
How many viruses and bacteria are there that are ready to attack my dog?
The biggest threat to your puppy and young adult dog is from Parvovirus. This dangerous virus is spread in vomit and diarrhea from sick pups. If you have a young pup, it needs to be vaccinated at least twice , with the last vaccine given after 16 weeks or four months. The vaccine at this time boosts immunity enough to protect the youngster when he or she comes in contact with a sick pup, vomit, or diarrhea in public places. Older vaccinated dogs are safe to hang around, because parvo is rarely seen in dogs older then 2 years old. I have only seen 2-3 cases of parvo in older dogs in 30 years.
It is important to remember that many “puppyhood diseases” like kennel cough, giardia, coccidia, and chewing on stuff diarrhea will occur and should be diagnosed and treated if severe symptoms are present
Some pups and adults will handle mild cases of kennel cough, giardia, and coccidia and not need treatment. I feel that exposure and mild infections often help the immune system stay tuned up. For example,I no longer treat all the dogs in the “family” because one member has “kennel cough” until the other dogs show signs of coughing or infection. However, that said, I am more inclined to treat senior citizens and young pups to be on the safe side, especially if they any have other immunity or medical issues.
Check with your veterinarian or their staff to see what are the most common infections in your particular area. Some of these infections can be avoided by vaccinating or medicating.
Remember that a dog in good health from eating a mix of healthy ingredients can fight off an infection faster and easier than a dog fed a poor diet and suffering from health problems
If you follow me on 
I have to admit part of the blame for puppy mills. My profession neuters almost every pet to prevent an epidemic of unwanted puppies. Veterinarians and the dog-owning public have given the responsiblity of puppy production to:
