Canine influenza update

by Dr. Kate Lawton

Canine influenza is a relatively new infectious disease caused by two separate viral strains – H3N8 and H3N2. First reported in Florida in 2005, H3N8 was recognized after a group of racing Greyhounds became ill (many fatally) with a severe and extremely contagious pneumonia. It has since been documented in 42 states, including New Hampshire. A few years ago, there was a reported outbreak at a kennel as close to us as Ipswich, Massachusetts.

H3N2 first emerged in 2015 in an outbreak in Chicago. This virus is of avian origin and not related to the earlier H3N8 virus, which is of equine origin; therefore, dogs at risk should be vaccinated against both viruses. Just recently Nobivac Canine Flu Bivalent has been launched. This vaccine aids in the control of disease associated with Canine Influenza Virus H3N8 AND H3N2 infection. Brentwood Country Animal Hospital has been offering this vaccine since November 2016.

The injection is administered once, followed by a second injection three weeks later. Side effects of the vaccine are rare and primarily consist of soreness at the vaccination site. Most local kennels, day care facilities, and groomers are not yet requiring the vaccine.

Canine influenza is spread via respiratory secretions and contaminated objects. Because this is a newly emerging virus, dogs have not yet developed any natural immunity regardless of their breed or age. All dogs are susceptible. 80% of exposed dogs will develop clinical signs, most of which are consistent with a mild upper respiratory infection usually accompanied by a persistent cough. However, a smaller proportion can progress to the severe form of the illness, resulting in a high-grade fever, pneumonia, and respiratory compromise. It would also appear that greyhounds and brachycephalic breeds (such as pugs and bulldogs) are at a higher risk for developing this more critical form.
Unless a secondary bacterial infection develops, treatment is largely supportive with good hygiene and proper nutrition. Most dogs will recover within 2-3 weeks and should be isolated from other dogs during this period.

So if the disease has rarely been reported in New Hampshire, why vaccinate? Right now, the animals that are most in danger of being exposed are those that travel to states where it's more prevalent, or those involved in competitions where dogs travel from distant states. Thankfully we haven't seen a huge spread into this area, which makes us a little less concerned about dogs that are groomed or boarded locally. (It's still possible for a dog to be exposed, but it seems a little less likely.) Many of our clients choose to forego our wonderful New England winters and travel southward. If you are one of these snowbirds, you should consider vaccinating your dog(s) prior to travel. At the time of this writing BCAH has not seen any confirmed cases of canine flu.

If you have any questions regarding canine influenza or would like to discuss whether your dog’s lifestyle increases the risk of exposure to the virus, please do not hesitate to contact us. We can help you determine whether or not the canine influenza vaccine is appropriate and safe for your pet.

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