Ohio and Michigan report H3N2v ‘swine flu’ infections linked to pigs at fairs

Four human infections with influenza viruses that normally circulate in swine (swine influenza) were reported by CDC this week. When swine influenza viruses are detected in people they are called “variant” viruses and are designated with a letter v at the end of the virus subtype. The four human infections were caused by H3N2v viruses in Ohio (2) and Michigan (2). All four patients reported attending fairs where they had exposure to pigs during the week preceding illness onset. Pigs at the fairs have reportedly tested positive for swine influenza A (H3N2) infection. The Ohio patients are not related other than both of them reporting having attended the same fair in Ohio. Similarly the Michigan cases both attended the same fair in Michigan, but are otherwise unrelated to each other. CDC is working with state public health officials to support their human health responses and has recommendations for the public on what steps they can take to help protect against H3N2v and other swine influenza viruses.