Abstract
Herpes simplex viruses have been divided into two types. These types may be differentiated by serological tests (Shubladze et al. 1960; Plummer, Waner & Bowling, 1968) and by the character of the lesions produced on the chorioallantoic membrane (CAM) of fertile hens' eggs (Parker & Banatvala, 1967) and in tissue culture (Lowry, Melnick & Rawls, 1971). It has been suggested recently that the serological classification into type 1 and type 2 may be too rigid and that a whole spectrum of variants may exist (Roizman et al. 1970).
The two types have a characteristic biological differentiation, type 1 being associated mainly with lesions of the face and type 2 with lesions of the genital tract. The observation that genital strains may be linked in some way with carcinoma of the cervix (Naib, 1966) has increased interest in these viruses.
Growth at different temperatures has proved a useful marker for several groups of viruses.