The state of New Jersey has reported one human infection with a novel influenza A virus. The individual was infected with an influenza A (H3N2) variant (H3N2v) virus. The patient was not hospitalized and has fully recovered from their illness. The patient visited a farm near where swine are frequently housed but no direct contact with swine was reported in the week prior to illness onset. No ongoing human-to-human transmission has been identified.

Image/Scott Bauer, U.S. Department of Agriculture
Image/Scott Bauer, U.S. Department of Agriculture

According to the Centers for Disease Control and Prevention (CDC), Swine influenza (swine flu) is a respiratory disease of pigs caused by type A influenza viruses that regularly cause outbreaks of influenza in pigs. Influenza viruses that commonly circulate in swine are called “swine influenza viruses” or “swine flu viruses.” Like human influenza viruses, there are different subtypes and strains of swine influenza viruses.

Swine flu viruses do not normally infect humans. However, sporadic human infections with swine influenza viruses have occurred. When this happens, these viruses are called “variant viruses.” They also can be denoted by adding the letter “v” to the end of the virus subtype designation. Human infections with H1N1v, H3N2v and H1N2v viruses have been detected in the United States.

Most commonly, human infections with variant viruses have occurred in people exposed to infected pigs (e.g. children near pigs at a fair or workers in the swine industry). In addition, there have been documented cases of multiple persons becoming sick after exposure to one or more sick pigs. Also cases of limited person-to-person spread of variant viruses have occurred.