The ongoing canine influenza outbreak in the Chicago area has been traced to a different strain of the virus than originally believed, and actually marks the first identification of the H3N2 subtype outside of Asia, according to Cornell University researchers.
Cornell issued a press release on Sunday (April 12, 2015) indicating that testing showed the outbreak was caused by “a virus closely related to Asian strains of influenza A H3N2 viruses,” not the H3N8 subtype that has been seen in the United States previously. This is the first identification of the H3N2 subtype outside of Asia, and the outbreak “suggests a recent introduction of the H3N2 virus from Asia,” the press release said.
It is not yet known if the currently available H3N8 vaccines will provide any cross-immunity to dogs exposed to the H3N2 subtype.
There is no evidence that the H3N2 subtype can be transmitted to people. However, it apparently has caused infection and respiratory illness in cats, according to both Cornell and the Center for Food Security and Public Health at Iowa State University. According to a canine influenza fact sheet from the Center for Food Security and Public Health: “The H3N2 canine influenza virus also seems to cause illness in cats. This virus was isolated from a cat that died during an outbreak of severe respiratory disease among dogs and cats at an animal shelter. … Antibodies to the H3N2 canine influenza virus have also been reported in apparently healthy cats.”
We have updated our canine influenza resources to reflect this discovery, and will continue to update them as needed when more information is available. We will also post updates on our social media channels, including Facebook, Twitter, Google+ and LinkedIn. AVMA members who would like to receive email updates of important news related to animal and public health, such as this discovery, can sign up to do so in our email subscription center.
Anyone with concerns about their pet’s health, or whose pet is showing symptoms of canine influenza, should contact their veterinarian. Symptoms of the disease may include a soft, moist cough or dry cough similar to that induced by kennel cough; discharge from the nose or eyes; sneezing; lethargy; low-grade fever; and loss of appetite.
Additional AVMA resources on canine influenza include the following: