Epstein-Barr viruses (EBV). Coloured transmission electron micrograph of Epstein-Barr viruses in Burkitt's lymphoma, seen as circles with inner coloured regions of nucleic acid (DNA). EBV, also known as human herpes virus 4, is 1 of 5 herpes viruses that attacks humans. In Europe & the US, EBV infection may produce glandular fever; in Central Africa it may lead to Burkitt's lymphoma (a facial cancer in children). In both cases the virus infects one type of white blood cell, the B lymphocytes. Infection with EBV is common & usually harmless; additional factors potentiate the development of more serious diseases. Magnification: x27,000 at 6x6cm size.