Colorized transmission electron micrograph of Rabies virus (red), which has heavily infected hamster kidney cells (green) cultured in the lab. Image by the National Institute of Allergy and Infectious Diseases (NIAID), USA, captured and color-enhanced at the NIAID Integrated Research Facility in Fort Detrick, Maryland, USA; image modified by MIC. The cover is published under the Creative Commons Attribution (CC BY) license.