Hepatitis C virus. Computer artwork of hepatitis C virus (HCV) particles (virions), the cause of hepatitis C liver disease. Each virion has a symmetrical protein coat or capsid (blue), from which project surface protein molecules (orange) that help the virus attach to its target cell. The capsid contains strands of RNA (ribonucleic acid, not seen), the virus' genetic material. Hepatitis C is most commonly spread by blood contact, through blood transfusions or the sharing of infected needles. It causes inflammation of the liver with jaundice and flu-like symptoms. There is currently no vaccine for hepatitis C. Cover credit: RUSSELL KIGHTLEY/SCIENCE PHOTO LIBRARY.