a close up of a blue object on a black background

This image depicts a 3D computer-generated rendering of a whole influenza (flu) virus, in semi-transparent blue with a navy-blue background. The virus’ hemagglutinin (HA), and neuraminidase (NA) surface proteins, are displayed in semi-transparent blue, sticking out of the surface of the virus. HA is a trimer, which is comprised of three subunits, while NA is a tetramer, which is comprised of four subunits, with a head region resembling a 4-leaf clover. Illustrator: Dan Higgins