Human alveoli from a single stem cell (IMAGE) Duke University Caption A single lung stem cell copied itself to generate thousands of cells and generate a bubble-like structure that resembles breathing tissues of the human lung. These are the cells that the SARS-CoV-2 virus targets. Credit Arvind Konkimalla/Tata lab, Duke University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.