H1N1 Flu Virus (IMAGE) University of Maryland Caption Pictured is a negative stain electron microscope image of the H1N1 Influenza virus that was responsible for the 2009 flu pandemic. Credit C. S. Goldsmith and A. Balish, CDC 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.