Abstract
Herpes simplex virus strains isolated from genital and nongenital sites were classified into type 1 (HSV-1) and type 2 (HSV-2) by endpoint neutralization tests using IgM of rabbits hyperimmunized with either HF (HSV-1) or UW-268 (HSV-2) strain. It was found that about one-third of the genital isolates belonged to type 1, in contrast to the general concept that HSV-2 represents genital herpes strains. These HSV-1 strains, differing from HSV-2, were mostly isolates from acute herpetic lesions of female patients with constitutional symptoms. On the other hand, all nongenital isolates except one were determined to be HSV-1. There was no intermediate type equally neutralizable by both types of IgM. A majority of the HSV-2 strains produced large plaques in chick embryo (CE) cells before passage through avian cells. In contrast, all HSV-1 strains failed to produce such large CE plaques even after serial passages through avian hosts.
