Herpes particles. Coloured transmission electron micrograph (TEM) of herpes virus particles in infected tissue. Each particle consists of a deoxyribonucleic acid (DNA) core (black) surrounded by an icosahedral (20-sided) outer coat (capsid, purple), which is itself surrounded by an envelope (orange). The herpes family of viruses cause a range of disease in humans, such as cold sores and genital herpes (herpes simplex viruses) and shingles (herpes zoster virus).