Coloured transmission electron micrograph (TEM) of Epstein-Barr virus (EBV) particles in Burkitt's lymphoma. Each particle consists of a deoxyribonucleic acid (DNA) core (red) surrounded by an icosahedral capsid (brown), which is itself surrounded by an envelope covered in glycoprotein spikes (yellow). EBV, also known as human herpes virus 4, is 1 of 5 herpes viruses that infects humans. It is best known as the cause of infectious mononucleosis (glandular fever), but is also associated with some forms of cancer, including Burkitt's lymphoma. In both infections, the virus infects one type of white blood cell, the B lymphocytes. Infection with EBV is common and usually harmless; additional factors potentiate the development of more serious diseases. Magnification: x135,000 when printed at 10 centimetres tall.