Fig. 5.

Preparation of a herpesvirus from a skin lesion negatively stained with PTA. The virion is surrounded by a limiting lipid bi-layer (‘fried egg’ appearance). This envelope is structurally and functionally an integral part of the virion. The virion appears to have a hexagonal outline (icosahedral morphology) and is covered with 152 tubular capsomeres. The members of this group of viruses all look identical, but each member of the group produces different symptoms. The internal virion of all herpes group viruses is about 100 nm in diameter and the complete virus with envelope is 150–180 nm.