Canine influenza, a reportable disease in Michigan, continues to be a topic of interest for Michigan companion animal veterinarians though the incidence of cases has substantially decreased since the July/August peak. As of August 31, 2018, the Michigan Department of Agriculture and Rural Development (MDARD) reported 147 confirmed cases in 12 counties. As of September 10, the case count is slightly up at 151. Most cases are in Oakland, Macomb and Kent Counties. Anecdotally, boarding kennels have been particularly hard hit. The majority of cases with strain type results have been H3N2. MDARD posts case numbers online and updates numbers periodically. You can track reported confirmed cases of canine influenza in Michigan (tracking is by number and county) on MDARD’s website.

There are a variety of educational resources available for veterinarians on canine influenza:

• The American Veterinary Medical Association has FAQ’s and comprehensive information on the disease, as well as handouts for clients (handouts are for members only and access requires a login).
• Michigan State University Veterinary Diagnostic Laboratory has a news update with a number of reference links including a link to a client handout they developed and a link to the Cornell University Canine Influenza Virus Surveillance Network. The surveillance network site provides information from cooperating laboratories for case counts in multiple states.
• The University of Florida College of Veterinary Medicine has information from their state’s outbreak in 2017 including a client handout in Spanish.
• Canine influenza vaccine manufacturers, Merck and Zoetis, have information for veterinarians and pet owners. Merck recently posted a webinar, Get the Dog Flu Facts, to provide a good overview of canine influenza and influenza in general. Merck also has a YouTube video suitable for dog owners. The Zoetis dog flu site has information for both veterinarians and pet owners.
• You may want to revisit information releases from MVMA and MDARD.

Overall, there is good medical information available about canine influenza. Starting with the information above can get you up to speed on the basics of disease spread, disease prevention and education for your clients. This is one of those diseases, though, where veterinarians may also benefit from thinking about population health in addition to thinking about individual patients. This is especially true when dealing with dogs that board, get groomed, attend doggy daycare and otherwise congregate and comingle, as so many of your canine patients probably do. Plus, do not forget about the triad of agent-host-environment when you look at the tools you have available to prevent and mitigate disease spread. Here are some thoughts to consider:

• Agent: Canine H3N2 is highly contagious. We should expect canine H3N2 to continue to spread in the United States with outbreaks occurring in dogs until mitigation practices become widespread and there is more widespread immunity in the dog population. Fortunately, this virus is not zoonotic; it has, though, been found in cats. The other canine influenza virus, H3N8, tends to be less contagious. H3N8 has a history of being an outbreak problem at race tracks.
• Host: “Social distancing” of dogs and vaccination are tools to protect dogs. Obviously, when dogs congregate, the virus has more opportunity to move from one dog to another. As with certain other diseases, widespread vaccination can be a major factor leading to population immunity. As noted in the recent Merck webinar, Get the Dog Flu Facts, though, vaccinating in the face of an outbreak is not particularly effective. This is because there is not enough time for a dog to complete the series of vaccinations and develop a full immune response. When deciding whether or not to routinely vaccinate a canine patient, current recommendations to evaluate the lifestyle of a pet (including opportunities for indirect contact such as dog parks or stores that allow pet visits) and vaccinate before there is an outbreak in the are reasonable. The other thing to remember about vaccination for this disease is that it does not stop infection, but it is thought to reduce shedding and result in milder clinical signs.
• Environment: The theme here is minimizing the number of virus particles and their opportunity to spread. This means preventing virus introduction, taking steps to minimize virus movement (think fomites), and cleaning and disinfecting to eliminate virus particles.

Now that the Michigan canine H3N2 outbreak appears to be diminishing, you may have some time to consider how you will deal with this disease in the future. Are there new or updated steps you can take in your practice to mitigate canine H3N2? Think about factors related to the virus, your canine patients, and the places you manage that house dogs. Veterinarians have been an integral part of curbing the recent H3N2 outbreak in Michigan and you can be even more prepared for future canine H3N2 incursions.

Veterinary hospitals in southeastern Michigan have seen a notable spike in canine influenza cases this summer, with Oakland and Macomb counties seeing the highest numbers of cases. As of August 13, there had been 98 cases reported in Michigan in 2018.

We have recently implemented new intake procedures for pets suspected of contagious respiratory disease to keep all our patients safe and healthy. Upon arrival, you may be asked to wait in the car with your pet and/or to use an alternative entrance so we can complete an evaluation.

Thank you in advance for your cooperation and understanding.

Veterinary hospitals in southeastern Michigan have seen a notable spike in canine influenza cases this summer, with Oakland and Macomb counties seeing the highest numbers of cases. As of August 13, there had been 98 cases reported in Michigan in 2018.

The H3N2 strain of Canine Influenza is a highly contagious respiratory disease and can spread quickly through a pet population. Aerosolized respiratory droplets can travel as far as 20 feet, and the virus can remain infective on hands for up to 12 hours, on clothing for up to 24 hours, and on hard surfaces for up to 48 hours.

Canine influenza spreads quickly through direct dog-to-dog contact, respiratory droplets suspended in the air from coughing, and contamination of water bowls, leashes, or kennel surfaces. People also can spread the disease from dog-to-dog via their hands and clothing. Dogs who frequent boarding, daycare, grooming, and dog park facilities may be at a higher risk of contracting the disease, but nearly all dogs exposed to the virus will become infected.

H3N2 first arrived in the United States in 2015 and is derived from an avian virus that is able to infect dogs. H3N2 Canine Influenza infections have been documented in at least 46 states, and outbreaks are currently active in New Jersey, Alabama, Massachusetts, New York, Iowa, Texas, Wisconsin, Indiana, Georgia, Illinois, and Michigan.

Vaccination against the two known strains of canine influenza (H2N3 and H3N8) is readily available for dogs and offered by many veterinarians, including MSU Veterinary Medical Center’s primary care service. The vaccines are effective in reducing or preventing disease, and also reducing the duration of viral shedding after exposure. The vaccine is recommended for any dogs living social lifestyles, which includes frequent boarding, socialization classes, day care, or dog parks, as well as for dogs who travel. Please contact your veterinarian or the MSU Veterinary Medical Center for more information on the Canine Influenza vaccines.

Symptoms appear 2-4 days after the dog is exposed to the virus and can last anywhere from 1-4 weeks. Dogs who are infected can immediately transmit the virus to other dogs within 24 hours and can shed the virus for as long as 4 weeks. This means a dog can spread the virus before it shows any symptoms of illness, and may continue to shed the virus as symptoms resolve.

• Coughing
• Sneezing
• Lethargy
• Fever (temperatures above 103 degrees)
• Discharge from nose and/or eyes

Most cases of H3N2 Canine Influenza are self-limiting, with symptoms typically resolving within 1- 4 weeks. More severe cases may require immediate treatment or hospitalization, as these dogs may also acquire additional viral or bacterial infections.

• If your dog is exhibiting symptoms, please contact your primary care veterinarian
• Keep your dog away from other dogs (confirmed cases should be quarantined for two weeks after symptoms resolve)
• When you arrive at your veterinary clinic, alert the staff before you bring your dog into the building
• Your veterinarian can obtain samples necessary to determine if your dog has H3N2

The Michigan Department of Agriculture is closely monitoring the number and location of canine influenza cases across the state. Regular updates are provided on their website at https://www.michigan.gov/mdard. Or contact the MSU Veterinary Medical Center at (517) 353-5420.