CIV – Canine Influenza Virus – N3HN
Written by Ronde Dalton & Kathy Molek
Sunday, 08 November 2009
The flu virus has long been recognized to cause disease in people and horses. However, the type of flu virus which causes disease has been species specific meaning that the people version of the virus infected people and the horse version affected horses without crossing species. Neither of these flu viruses was known to infect dogs at all. Somehow a change, mutation, occurred in the horse flu virus at a racetrack in Florida in 2003. The horse virus infected a kennel of racing Greyhounds. The respiratory illness that resulted caused fevers, coughing and discharge from the nose and eyes of the sick dogs but the illness was not immediately recognized as a new disease. So, dogs from the kennel were not isolated and as these dogs traveled, the disease traveled and spread with them.
Canine flu is now a recognized and established dog disease. The canine flu does not infect people. And, the people flu still does not infect dogs. Canine flu is highly contagious and spreads very easily from dog to dog as it is a new disease to dogs and preexisting immunity to it does not exist. Nearly 100% of exposed dogs will catch the virus. The good news is that the vast majority, over 80%, of exposed dogs will either never appear to be sick or will have very mild, transient symptoms and recover. The other 15 to 20% of dogs will have obvious illness with coughing, fevers, lethargy, nose and eye discharges. And, a small percentage of dogs, 1 to 5%, will have severe enough illness to develop pneumonia and die. The dogs at risk to become the most ill are analogous to the people who do become the most ill from people flu— the very young, the elderly, and those already compromised by any other disease.
A new vaccine exists. This vaccine is very recently released for use; so, no long term data exists as to its long term benefits, risks, or possible adverse effects in the general population of pet dogs. The vaccine must be given in two injections and a dog is not protected until three weeks after the second injection. An initial vaccine is given and then a second vaccine administered 3 to 4 weeks after the first. The manufacturer of the vaccine does not claim the existence of protective immunity until 3 weeks after the second vaccine. A yearly booster is then required.
Evidence does exist that the first vaccine injection, after a few days, will help to decrease the number of virus particles a subsequently infected dog will shed into the environment. Not that your dog will be protected against sickness, just that once sick, your dog will be less contagious to others. This benefit again does not occur immediately as soon as the first booster is given rather develops in 7 to 10 days. An initial vaccine administered on the day a dog enters a kennel to board will not protect your dog nor any other dog. Even, a second vaccine administered on the first day of boarding will not protect your dog.
So, if you decide that your dog’s risk to contract flu is significant enough to warrant the use of this new vaccine, you must also realize that your dog cannot be considered protected until a minimum of six weeks after the first vaccine is administered and only if your dog receives two vaccine injections.
Canine flu is a real disease. It is a disease of only dogs— not cats or people. It can be a serious and fatal illness for a very small minority of dogs. Distemper, Parvovirus, Parainfluenza, Canine Hepatitis, Leptospirosis diseases are all vastly more deadly diseases with mortality rates of 30% or more of infected dogs. Rabies of course has a 100% mortality rate. So, while canine flu is certainly a disease of which to be aware, consider carefully whether enough risk exists for your pet before deciding on whether or not to vaccinate your pet. If your kennel, groomer, or day care requests vaccination against flu, remember the lag time until protection occurs, that the vaccine is still very new, and that the incidence of mortality from the disease is very low. Informed kennels, groomers, and day care providers will often allow you to opt out of vaccinating by signing a wavier that acknowledges you understand the disease and its risks.
