An undated electron microscope image made available by the U.S. National Institutes of Health in February 2020 shows the Novel Coronavirus SARS-CoV-2, yellow, emerging from the surface of cells, pink, cultured in the lab. Also known as 2019-nCoV, the virus causes COVID-19. The sample was isolated from a patient in the U.S. On Thursday, March 5, 2020, Tennessee's Department of Health Commissioner Lisa Piercey confirmed the state's first case of the new coronavirus.