Herpes simplex virus infection. Coloured transmission electron micrograph (TEM) of a section through a cell being destroyed by herpes simplex virus infection. At centre is a large cluster of viral capsids (protein coats, red) which the cell has produced at the direction of the virus's genetic material. There are also many mature virus particles which consist of the capsid surrounded by a lipid envelope, giving them a double circle or fried egg" appearance. Herpes simplex is a DNA virus. It is a very common pathogen in humans, causing fluid-filled blisters. Magnification unknown."