The state of Michigan saw an increase in cases of dog flu this year. More than 160 cases were reported in the state. Dr. Stephen Carey, a professor in small animal clinical sciences in the college of veterinary medicine at Michigan State University, said compared to last year, this year’s increase was fairly strong. “In climates like Michigan, where we have really harsh winters, that tends to be more frequent over the summer,” Dr. Carey said. According to the Ingham County Animal Control and Shelter, the flu infection started out in southeast Michigan in the Detroit area.