1969 Volume 43 Issue 2 Pages 37-43
An epidemic of rubella occurring among recruits of the Japanese Ground Self-Defence Forces (JGSDF) at Ohtsu Base Camp in Ohtsu city in a period from the middle of May to the end of July 1967 was outlined in the previous report, Report 1., in this magazine.
In this paper, the results of sero-epidemiological observations were presented.
1) Hemagglutination-inhibition test of rubella viruses was carried out on 12 cases who initialed this epidemic. In them, significant rise of the antibody was shown between acute and convalescent stage. In spite of the negative results of virus isolations performed on these patients in the acute stage, the seroimmunological evidence in them is strong enough to support the confirmation of their rebella infection.
2) At the very beginning and the end of the epidemic, a half number of all recruits belonging to two companies, in which the disease was prevalent, was extracted by random sampling and tested for HI level.
Antibody possessing rate was 61/121 at the beginning of the epidemic and turned to 116/121 at the end in one company, and 66/145 turned to 145/145 in the other. According to this result, the authors estimated that almost 50% of recruits at Ohtsu Base Camp had already possessed the antibody before the epidemic, and almost all the members were infected with the viruses by the end of the epidemic.
3) In this epidemic, the ratio between the latent and the manifested among supposedly newly infected cases was estimated about 1: 1.
