(a) Cross-neutralization testing on 6 JEV strains using polyclonal mouse antisera inoculated with different JEV strains: Nakayama, Beijing-1, P19-Br, LaVS56, and LaVS145. Vertical line: neutralizing antibody titers against JEV strains: Nakayama (Nak), Beijing-1 (BJ), JaGAr#01 (JaG), P19-Br (P19), LaVS56 (L56), and LaVS145 (L145) in a log10 scale. (b) The reactivity of sera from JE patients of different regions: two cases of JE (A: acute sera, C: convalescent sera) from Vientiane, Lao PDR, in 1994; eight cases from Chiang Mai, Thailand, in 1991; and two cases from Okinawa, Japan, in 1991. Vertical line: neutralizing antibody titers against JEV strains as panel (a).