Frequency of Australia Antigen among Children and Adults in Southern Japan

Abstract

Serum specimens obtained from 1325 people living under various conditions in southern part of Japan during the period 1969 through 1971 were investigated for Australia antigen (Au-Ag). Testing for Au-Ag was done by micro-Oucterlony's method (MO) using AUS-tect supplied by Abbott Laboratories and single radial immunodiffusion. test (SRID) using Eisai plate supplied by Eisai Company.
Test method and AU-Ag positive rate:
Out of 828 serum specimens tested, 27 were concommittantly positive by the both MO and SRID, and only one case showed a split (MO negative and SRID positive).
Districts, living and physical conditions, age and AU-Ag positive rate: Positive rate was 1.4% out of 221 outpatients under 25 years of age in a hospital in Fukuoka city, Kyushu island; positive rate was 5.6% in 305 inhabitants of Iriomote island (southernmost island of Okinawa), in that, the percentage was increased as the age was getting smaller-26% in age 5-9, and 14 (80%) out of all 17 AU-Ag positive cases were under 16. Eight cases (47.1%) were found positive intrafamilially (2 or 3 members in 3 families each); In pregnant women in Amami Islands, only 0.9% out of 347 were found postitive; Among institutionalized children, the frequency of AU-Ag was 4.0% in crippled patients in Kitakyushu city, 3.4% in 116 mentally retarded patients in Oita prefecture and none in 79 severe psychomotor retarded children in Fukuoka city; There was no positive case among 31 patients with Down's syndrome at home and among 5 patients with infantile hepatitis.
These data indicate that subtropical climate is one of the important factors influencing the epidemiology of AU-Ag and the possibility of intrafamilial infections cannot be denied.