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.
Canine influenza is highly contagious and 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 can also 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.
“Canine influenza can infect any dog, but the dogs at highest risk are those that live social lifestyles,” said Stephan Carey, assistant professor for small animal clinical sciences in the College of Veterinary Medicine. “Exposure to the virus typically occurs where dogs are closely commingled, including dog parks, day care settings, and socialization classes.”
Fortunately, the majority of dogs that contract canine influenza will have only mild to moderate illness primarily consisting of coughing and sneezing, although nasal discharge, lethargy, fever and decreased appetite are not uncommon.
“Nearly all dogs exposed to Canine Influenza will become infected and will shed the virus, while approximately 80 percent of the dogs exposed to the virus will go on to develop respiratory symptoms including coughing, sneezing and nasal discharge,” said Carey. “It is the remaining 20 percent of dogs who become asymptomatic shedders that allow outbreaks like the current one to occur.”
Symptoms usually resolve after two to three weeks, which is longer than other common respiratory pathogens. Severe illness is less common, but canine influenza can develop into a life-threatening pneumonia.
Dogs that contract canine influenza also have the potential to remain contagious for three to four weeks after initial infection. During this time period, they should be kept away from other dogs and cats, and pet owners should be careful not to inadvertently spread the disease to other pets on their hands or clothing.
Cats can contract canine influenza, but it is less common. There have not been any documented cases of humans infected with the H3N2 strain of canine influenza currently affecting 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. It consists of a series of two injections typically administered two to four weeks apart. Although vaccination cannot fully prevent canine influenza, it will lessen the duration and severity of clinical signs.
If your pet is ill and showing signs consistent with infectious canine respiratory disease, which may include canine influenza, you are encouraged to contact your veterinarian for further directions. If an examination is warranted, special precautions may be needed to prevent the spread of the virus within the hospital and, therefore, it is important to notify the office or hospital before arriving.
Testing for canine influenza utilizing nasal and throat swabs is widely available, and as is the case with most “flu” viruses, treatment generally consists of supportive care.
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 (https://www.michigan.gov/mdard/0,4610,7-125-48096-474844--,00.html). Or visit the College of Veterinary medicine’s resource page (cvm.msu.edu/hospital/canine-flu) , or contact the MSU Veterinary Medical Center (517)353-5420.