How Merck Animal Health
Helped to Curb a New
Strain of CIV

When a new strain of canine influenza emerged last year, Merck Animal Health hit the ground running to help protect dogs.

The Canine Influenza Virus

In March 2015, veterinarians in Chicago began reporting an alarming number of dogs showing signs of an infectious respiratory disease, with symptoms ranging from coughing, lethargy, to fever. Some dogs even developed pneumonia. What was initially thought to be a strain of “kennel cough” (aka: Infectious Canine Tracheobronchitis) was eventually identified as something more severe: The canine influenza virus (CIV), a highly contagious and serious disease.

“Early on, we suspected veterinarians were dealing with an outbreak of canine influenza and not kennel cough, which spurred us to implement the collection of nasal and pharyngeal samples from sick dogs that were tested by Cornell University,” said Kathleen Heaney, D.V.M., executive director, Companion Animal Technical Services, Merck Animal Health.

We came to realize what was actually unfolding was the transmission of an influenza strain – H3N2 – never before seen in the United States.

Based on the highly contagious nature of the strain, the severity of it, as well as the rate at which they were seeing newly diagnosed cases, Merck Animal Health knew they needed to act fast —both to help veterinarians and pet owners contain the outbreaks and develop a vaccine to protect dogs against it.

Dog flu is passed through direct and indirect contact with an infected dog. What makes CIV H3N2 even more of a problem is that an infected dog can be infectious for up to 24 days. Social dogs that visit dog parks, doggie day care, kennels and groomers are at most risk.


Merck Animal Health quickly set up webinars for veterinarians, utilizing experts in the field of virology and immunology. The multiple webinars reached more than 5,000 veterinary professionals across the U.S. and gave them tools they could use to help address CIV. Merck Animal Health also initiated an educational email campaign to more than 26,000 veterinarians to create awareness among veterinarians in states that had not yet been affected.

“In the face of an outbreak, it is critical to be transparent and share accurate and up-to-date information with all involved,” says Chicago-based Merck Animal Health veterinarian Joseph Hahn, who worked to help curb the outbreak.


The Merck Animal Health team helped veterinarians prepare for interviews with the media about canine influenza. The team developed educational materials for veterinarians to share with their clients about keeping dogs healthy. Additionally, the team provided pet owners with tips on how to stop the spread of the virus through multiple communication channels.

Eight months after identification of the new strain, Merck Animal Health received approval for a conditional license for its H3N2 vaccine. Merck Animal Health began shipping the vaccine the day after approval.

Thirty states affected by H3N2

Since the first outbreak in 2015, 30 states have reported cases of H3N2 canine influenza. Merck Animal Health’s awareness-raising efforts have generated hundreds of reports on social media channels and news outlets, such as Bloomberg, Huffington Post, Pet World and others.

In the U.S.:

Nearly 78 million pet dogs

54 million households own dogs

If This Dog Could Talk

This year, Merck Animal Health launched a multi-city tour of pop-up events to help educate dog owners about canine influenza. Called If This Dog Could Talk, the events included information sessions with local veterinarians as well as photographer Elias Weiss Friedman from The Dogist who was on hand to photograph attendees' furry friends.