Scientist with the Centers for Disease Control harvesting influenza A virus subtype H7N9 that has been grown for sharing with partner laboratories for research purposes. On April 1, 2013, the World Health Organization first reported 3 human infections with a new influenza A (H7N9) virus, a type of avian influenza (bird flu), in China. Most reported cases have severe respiratory illness and, in some cases, have died. At this time, no cases of H7N9 outside of China have been reported.