Influenza (IMAGE) Whitehead Institute for Biomedical Research Caption When exposed to the influenza virus, normal cells (left) were infected with the virus (stained green). The virus was unable to infect cells with mutant versions of an enzyme that it needs to take over the cells (right). Credit <I>Science</i>/AAAS Usage Restrictions With credit 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.