New Canine Influenza Virus vaccine for H3N2 available | Dr. Justine Lee

With the recent H3N2 Canine Influenza Virus (CIV) outbreak that started in Chicago, IL in early spring of 2015, pet owners and veterinary professionals have been worried about their own dogs and patients. Initially, there was some thought that this outbreak was due to H3N8, but through diagnostic testing, it turned out to be due to H3N2 (a virus originally found in China, Korea, and southeast Asia), which had never been reported in the United States before.

Hundreds of dogs were affected by CIV H3N2 in over 24 states, including Illinois, Wisconsin, Iowa, Texas, Michigan, California, Indiana, Minnesota, New York, New Jersey, Georgia, North Carolina, South Carolina, and more.

Canine Influenza Virus due to H3N2 Spring 2015 Outbreak

Clinical signs of Canine Influenza Virus H3N2 include:

• Coughing
• Nasal discharge
• Not eating
• Fever
• Lethargy
• Inappetance progressing to anorexia
• Increased respiratory rate
• Difficulty breathing

This week, Merck Animal Health announced that they have pioneered an H3N2 Canine Influenza Virus vaccine. The U.S. Department of Agriculture (USDA) has issued a conditional product license for a vaccine to protect against this newly identified strain of CIV. According to Merck Animal Health, the CIV H3N2 vaccine will be available to U.S. veterinarians beginning next Monday, November 23.

“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., 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 clinical disease and the rate at which we were seeing newly diagnosed cases, we knew we needed to act fast – both to help veterinarians and pet owners contain the outbreaks and develop a vaccine to protect dogs against it.”

According to clinical studies by researchers at the University of Wisconsin, the CIV H3N2 may be shed for an extended period of time – up to 24 days, which is far longer than what is seen with CIV H3N8. As a result, the infection can spread quickly among social dogs in inner cities, doggie daycares, boarding facilities, dog parks, sporting and show events and any location where dogs commingle.

“Based on experimental studies in Asia and the rate of spread we’ve observed, I would estimate that H3N2 produces 10 times more virus than H3N8, which makes it far more contagious,” said Edward Dubovi, Ph.D., Professor of Virology and Director, Virology Laboratory, Animal Health Diagnostic Center, College of Veterinary Medicine, Cornell University. “Preventing the transmission of the disease through vaccination is highly recommended for those dogs that have lifestyles that put them at greater risk.”

CIV can be spread by direct contact with respiratory discharge from infected dogs, through the air via a cough or sneeze and by contact with contaminated objects such as dog bowls and clothing or by people moving between infected and uninfected dogs.2 According to the U.S. Centers for Disease Control (CDC), there is no evidence of transmission of the virus from dogs to people.

The Canine Influenza Vaccine H3N2 is recommended for healthy dogs 6 weeks of age or older as an aid in the control of disease associated with canine influenza virus H3N2 infection. The type A, subtype H3N2 virus has been chemically inactivated and combined with an adjuvant designed to enhance the immune response. The vaccine is conditionally licensed and there is a reasonable expectation of efficacy.

As part of our continuing support of science and healthy animals, Merck Animal Health will continue its work within the industry to help develop a better understanding of this disease, including its participation on the H3N2 task force created earlier this year, hosting educational webinars for veterinarians and providing informational materials on managing the outbreak for clinics and pet owners. For more information about CIV or to access CIV materials, please visit doginfluenza.com.