More than 90 spices of herpes viruses have been isolated from wide variety of non-human animals. Among these herpes viruses, only B virus (Cercopithecine herpesvirus 1), the natural host of which is macaque monkey, is severely pathogenic to human. B virus infects human through handling infected monkey tissues or by injury caused by infected monkey, and severe encephalitis ensues. However, in 1997 mucocutaneous infection without injury was reported. The genome structure and immunogenic property of B virus is similar to those of human herpesvirus(HSV). And pathogenecity of B virus to monkey is also similar to that of HSV to human. Although the natural host of pseudorabiesvirus (Suid herpesvirus 1) is swine, it infects wide range of animals and causes severe nervous symptoms. However, the pathogenicity to human is controversial.