New Nomenclature for Swine-Origin Influenza

The U.S. Centers for Disease Control and Prevention now has a new nomenclature for swine-origin influenza viruses identified in humans. It will now be referred to as “variant” viruses and denoted with a “v.” Influenza viruses identified in swine populations will continue to be referred to as “swine influenza” viruses. The decision was made after discussions among the World Health Organization, the World Organization for Animal Health, the Food and Agriculture Organization, CDC, and other U.S. federal agencies.

The CDC says human infections with the influenza viruses currently circulating among swine are rare. Since 2005, only 35 cases have been reported in the United States, but the frequency with which they have been detected increased in 2011. Since August 2011, CDC has identified 12 human infections in five states with swine-origin influenza A (H3N2) viruses.

To minimize the risk for interspecies influenza transmission, CDC and the Occupational Safety and Health Administration encourage swine workers to be vaccinated against human seasonal influenza, wear appropriate personal protective equipment, and practice good hygiene, such as washing hands thoroughly with soap and water, when in contact with swine, especially swine that show signs of illness.