The outbreak of canine influenza virus (CIV) has spread to other areas of the Midwest as reports put the total case count to over 1,300 affected dogs and at least six deaths in some four states to date.

Image/Amanda Mills
Image/Amanda Mills

The respiratory illness that first reared it’s head in the Chicago-area, has now also been reported in Indiana, Ohio and Wisconsin.

The Indiana State Board of Animal Health doesn’t put a specific number (estimate of about a dozen have been reported) as to how many dogs have been affected, but do say that dog owners can take steps to protect their pets: “While no significant number of cases has been reported in Indiana, Hoosier pet owners can take steps to protect their dogs.

“Canine influenza is a highly contagious disease that spreads easily among dogs,” said Sandra Norman, a veterinarian for the Indiana State Board of Animal Health (BOAH). “Dog owners who travel with their pets to infected areas or take them to places where many dogs congregate (like dog parks or kennels) should consider vaccinating their animals.”

In Wisconsin, dog flu has been reported in the state, including in the capital of Madison.

Concerning new scientific developments on the canine influenza, the folks at the University of Wisconsin-Madison say the implicated virus, H3N2, is virtually identical to an Asian strain of the virus and is not a mutated form.

Genetic sequencing conducted at the National Veterinary Service Laboratory in Ames, Iowa, now confirms that the H3N2 strain found in the Midwest is almost identical to its Asian counterpart and was likely brought to the United States by an infected animal.

“This means there is no evidence of genetic reassortment,” says Kathy Toohey-Kurth, virology section head at Wisconsin Veterinary Diagnostic Laboratory (WVDL). “This is good news because mutations are unpredictable, and we would not necessarily know what the safety implications are for humans or other animals.”

There is no evidence at this time that the H3N2 CIV strain can infect humans; it is distinctly different from human seasonal influenza H3N2 strains. However, the Asian H3N2 CIV strain has been reported to infect domestic cats.

“No cats have reported positive in the United States at this time,” says Keith Poulsen, WVDL diagnostic and case outreach coordinator and clinical assistant professor at the UW-Madison School of Veterinary Medicine (SVM). “Two cats and a dog, housemates of the infected dog in the Madison area, tested negative today despite showing clinical signs of the virus. It’s possible the tests were done too late to catch the viral shedding phase. Either way, it’s good news for those animals.”

The commercially available vaccines for CIV are made to protect against the H3N8 strain, and their effectiveness against the H3N2 strain is unknown at this time, but it is likely to be less effective.

“We’re still recommending that owners vaccinate their dogs because H3N8 is still around,” says Sandi Sawchuk, primary care veterinarian at UW Veterinary Care (UWVC) and SVM clinical instructor.