Geographic localization of three variants of herpes simplex virus type 1 in Japan

: We previously reported that a variant of herpes simplex virus type 1 (HSV-1) designated variant type A was isolated at a much higher frequency in Western Japan than in Eastern Japan. We examined the localization of two other variant types designated B and C. The proportion of the type B and type C variants among 553 fresh HSV-1 isolates from 10 areas in Japan were 5.4% and 1.3%, respectively. The isolation frequency of type B variant in Eastern Japan was 8.3%. It was as high as 20.5% in Iwate area. The frequency in Western Japan was only 3.0%. Type C variant showed no specific geographic localization. These results were discussed in terms of characteristic mode of HSV infection and the history of the Japanese nation.