Studies of Rubella Virus

During the rubella epidemic of 1966-1967 in Yamaguchi, one hundred and twenty-seven patints with rubella were studied virologically and seroimmunologically, and the following results were obtained : (1) Concerning the isolation of rubella virus, the direct method using primary rabbit embryo cells was investigated and compared with the indirect method using African green monkey kidney cells and it was found that RE cells were almost the same as GMK cells for susceptibility to rubella virus, that RE cells showed simple cytopathic changes which could be observed directly, and they were very simple to obtain and to manage so that they are well suited for studies of rubella virus. (2) From l27 patients, 48 strains (37.2 %) of rubella virus were isolated by the indirect method using GMK cells and 46 strains (36.2 %) were isolated by the direct method using RE cells. (3) From 6 patients with rubella encephalitis, two strains of rubella virus from throat swabs and one strain from cerebrospinal fluid were isolated. (4) From a fetus, after artificial abortion, of a mother who had had rubella at an early stage of pregnancy, rubella virus was isolated suggesting the possibility of a congenital rubella syndrome. (5) Fifty-four cases (87.0 %) out of 62 cases of rubella patients, pair sera were obtained, showed neutralizing antibody titer rising more than 4-fold. (6)The antibody response of 126cases of pregnant women to rubella virus was examined and found to be under 4-fold in 19 cases (15.1 %) and above 4-fold in 107 cases (84.9%).