Herpesvirus. Coloured transmission electron micrograph (TEM) of a herpesvirus virus particle (virion). The herpesvirus group includes the viruses that cause chickenpox, shingles, herpes and cold sores. The protein coat of the virus, the capsid (red), encloses the genetic material (not seen). The capsid is surrounded by an irregular lipoprotein envelope (yellow). Herpesviruses cause vesicular eruptions, after which they may become dormant in the nervous system, often becoming reactivated at a later date. Magnification unknown.