The herpes group consists of viruses which have been placed together on
the basis of a number of distinguishing features that they share in
common (ANDRE- WES, 1962). All these viruses are relatively large,
possess identical morphological characteristics, contain DNA, and are
extremely sensitive to inactivation by ether; these viruses are also
assembled within the nucleus of the host cell and induce the formation
of eosinophilic intranuclear inclusions. The epidemiology of some of the
best known viruses in this group (herpes simplex, pseudorabies, and
B-virus) is also similar (BURNET et aI., 1939). Herpes simplex virus
exists in the latent state in man, the natural host for this virus, and
becomes overt in individuals subject to some form of stress; this
condition appears to be paralleled by pseudorabies virus in its natural
host, swine and by B-virus in monkeys. In each instance, transmission of
the virus to a susceptible host other than the natural one results
usually in marked symptoms and death. This chapter is confined to a
description of herpes simplex and pseudorabies viruses; B-virus is
described separately elsewhere in the Hand book. Since the clinical
aspects of the diseases caused by herpes simplex virus and pseudorabies
virus have been well described, greater emphasis will be placed,
therefore, on the basic biological and biochemical properties of these
viruses; their clinical features will be discussed only briefly.