Epstein-Barr virus particles. Coloured transmission electron micrograph (TEM) of Epstein- Barr virus (EBV) particles (yellow) being shed by a malignant (cancerous) white blood cell. EBV is a member of the herpesvirus family (it is also known as human herpesvirus 4). It is a common virus, found in up to 90% of the population, often lying latent and so not causing any disease. However, EBV can cause a number of diseases, especially in immune-suppressed individuals. These diseases include glandular fever (infectious mononucleosis) and a variety of lymphomas (cancers of white blood cells) and nasopharyngeal carcinoma. The cell infected here is an immature t cell (t lymphoblast). Magnification: x25000 at 10cm wide.