Considering Canine Influenza

posted: by: Dr. Margaret Eastman Tags: "Clinic Specials" "News" 

In March of 2015, the Chicago area experienced a pretty significant outbreak of Canine Influenza Virus (CIV) H3N2. Prior to that, CIV had been limited to a handful of racing greyhound populations and was caused by the H3N8 strain. (From the human side, does this variation sound familiar?) According to the veterinary diagnostic lab at Cornell University, they had two positive and a handful of negative tests from our area between March 2015 and September 2016. There has been one confirmed positive in Brown County during the last 45 days.

Keep in mind that CIV is one of a handful of viruses and bacteria that can cause upper respiratory signs such as a cough or runny nose. There were a number of dogs who presented for cough who tested negative for CIV, so another bug presumably caused their symptoms. Dogs at risk for all of these infections are those who spend time in larger groups – daycare, boarding, performance events, the dog park, and shelters.

When the outbreak happened last spring, the only CIV vaccine on the market was for the H3N8 strain, not the H3N2 strain that was the issue. Since then, the H3N2 vaccine has become available and a combination vaccine is on the horizon. Though none of the boarding kennels in our area are requiring the CIV vaccine, several are recommending it. So what are you to do?  There’s no clear-cut answer, but here are some points that we hope will help you make a decision.

First, read this article from the AVMA:

So the argument for vaccination:

Canine influenza is highly contagious and does cause disease in the vast majority of infected dogs. Dogs who contract the disease can shed virus for 21 days. Most aren’t ill for that long, but they shouldn’t have contact with other dogs for 3 weeks. Though the symptoms are mild to moderate in most dogs, some can develop pneumonia.  Treatment involves a trip to the veterinarian and often a course of antibiotic. This seems counter intuitive, but despite this being a viral infection, antibiotic does seem to help resolve the symptoms sooner. CIV can be challenging to diagnose. To confirm with a technique called PCR, a nasal swab had to be collected in the first two days when symptoms occurred. These dogs weren’t overly ill, so they often didn’t visit the clinic in time for a valid test. It’s likely several of these cases went undiagnosed yet responded to treatment and all was well.

The limitations of vaccination:

It’s not clear how substantial a roll CIV played in our last outbreak of the collection of infections dubbed “kennel cough,” and there is no outbreak going on now. Granted, we routinely vaccinate our dogs for diseases they may never see, but the difference is that this disease is not typically life-threatening. And because of its ability to mutate, influenza virus is a bit of a moving target. The strain that’s an issue today may not be in the next outbreak. And we have no idea if and when that outbreak will occur. We may vaccinate for H3N2 this year, then run into a completely new strain next time. And just like the Bordatella vaccine, there are other infectious agents that cause dogs to cough. This vaccine is no different.  It greatly reduces the risk of CIV infection, but not all causes of “kennel cough.”

Vaccination, both on the veterinary and the human side can be a controversial topic. We all agree vaccines are valuable tools in reducing disease outbreaks, but there is an ongoing debate over how much is too much. That’s why we’re providing this information to you. It’s reasonable for a facility to recommend this vaccine, but you also need to know the limitations so you can make an informed decision.

We carry the H3N2 vaccine now. A first dose is given and is then repeated once three to four weeks later. If your dog is otherwise current on his or her wellness exam and vaccines, a technician can start this series for you.  Please don’t hesitate to contact us with any remaining questions.

Drs. Skaletski, Riedi and Eastman