By: Fiona Lee Caldwell DVM
For Pets Best Insurance

It’s just about flu season! Did you know that dogs have their own flu bug as well? Here’s what you need to know about the canine flu to ensure proper pet health this season.

Influenza, affectionately called the flu, is a virus that causes upper respiratory illness in animals and people. For the most part, the virus is very species specific, meaning dogs can’t catch swine flu or avian flu or even the human flu. However, the influenza virus is a unique virus that mutates, or changes, at a rapid rate. It can change significantly even during one flu season. This is why researchers spend so much time determining what the new influenza virus will act like each year in order to prepare a vaccine. This mutation rate also means it is possible, but rare, for the virus to change enough to infect a different species.

It has been recently proven that the canine influenza virus was originally the horse influenza. Twenty two greyhound dogs on a racetrack in Florida came down with respiratory infections in January of 2004.

Subsequent identification of flu infected dogs throughout the United States from 2003 to 2005, support the theory that a single virus mutation from horses to dogs occurred. In addition, the new mutated canine virus was able to be transmitted from dog to dog. To date, about 30 states and the District of Columbia have confirmed influenza infections in dogs. Most of these are in shelter settings.

Clinical signs of the canine flu include most commonly a mild cough with fever. Ten percent of infected dogs will show no clinical signs at all, but can ‘shed’ the virus, meaning other dogs can catch it from them, even though they aren’t sick. Most pets, about 80% with mild cough, recover without treatment. Some will require treatment with hospitalization, but rarely. While it is true that some dogs can develop severe illness and there have been some reports of deaths, this is uncommon. Canine influenza is not a highly fatal disease; mortality rate is about 6%, and likely to be even less in a clinical/hospital setting versus research or shelter setting. Like human influenza, the canine virus is very contagious, if exposed, most dogs will develop antibodies to it, but not every dog will get sick.

Treatment, when indicated, generally involves antibiotic therapy in addition to supportive therapy such as intravenous fluids and nutritional support. Dog health care can be compromised, and the virus can be ‘caught’ through causal contact, aerosolized nasal secretions, or shared bowls and toys.

These reports of canine influenza led researchers to develop a canine influenza vaccine in July of 2009, which is now available at many veterinary clinics. Here are some important facts to remember prior to getting the vaccine. It doesn’t prevent your dog from becoming infected, and it does not prevent shedding (infectivity). It has been shown to lessen the severity of the respiratory illness your dog develops. Most vaccinated dogs will have a shorter, milder course of illness. For optimum dog health care, two doses are necessary for protection and length of immunity is unknown at this time. The manufacturer recommends annual boosters.

The risk of your dog contracting canine influenza is low. Some states have never reported any cases of influenza at all. Most veterinary clinics consider the vaccine non-core, meaning experts are not recommending the vaccine unless there is an unusual circumstance, such as plans to travel, exposure to racetracks or exposure to shelter settings. There is, however, an indication for shelter housed animals, as an outbreak and threat of infection is higher, with more detrimental consequences.

It is important to assure pet owners that there is NO evidence there is any risk of spread of canine influenza to people. If you have more questions about the canine flu or the influenza vaccine, contact your veterinarian.

*Pets Best Insurance does not cover the canine influenza vaccine