健康乳幼児糞便よりの腸管系ウイルス分離について

抄録

During the period from February 1957 to July 1958 in Osaka, the author collected 447 fecal specimens (2.4per person) from 190 healthey infants and children under 4 years and 11 months of age who were inoculated with Salk's vaccine; attempted the isolation and typing of enteroviruses on these specimens by using human-embryonic tissue cultures.
The sera were collected from those individuals and tested neutralizing antibodies against entero viruses, particulary ECHO-7 and ECHO-12.
The results are as follows:
1) Sixty-seven strains of enteroviruses were isolated from the feces: fifteen percent of the specimens or 28.9 percent of the individuals examined yielded cytopathogenic agents.
2) The typing of the isolated agents revealed as follows: 13 strains of Echovirus 12 (E-12), 11 strains of E-7, 7 strains of E-6, 5 strains of E-11, 2 strains of poliovirus type II, 5 strains of polio-virus type III and 24 untypable strains (other than poliovirus types I, II, III, E-1, E-2, E-3, E-5, E-6, E-7, E-9, E-11 and E-12) were identified.
3) 62 of 67 strains (92per cent) were isolated from the specimens taken on September and October 1957. Therefore, it is considered that the isolation rates are higher in summer and early fall and lower in winter.
4) As far as the author examined, significant difference of the virus isolation rate was not found among various age groups. The reasoning may be that the age of the examinees was generally young to show such difference.
5) The residences of the virus carriers were located in three provincial districts around Osaka, and the local prevalence was not found in these three areas.
6) Twelve individuals excreted the virus in two specimens taken over a month apart. There-fore, the period of excretion was over 37 days in one instance of E-7 infection, three instances of E-12 infection, and over 51 days in one instance of poliovirus type III infection.
7) The homotypic antibody rise was found in all the carriers of E-12 and 9 of 10 carriers of E-7 viruses. Since the first serum specimens of those individuals showed no antibody to the infected agents, they were considered as primarily infected with such enteroviruses. Three of 45 carriers who excreted the virus other than E-7 and E-12 showed antibody rise against E-12, and one of 42 carriers belonging to the same categorie above showed antibody rise against E-7. The neutralization tests of the sera pooled by age and date of bleeding revealed the prevalence of E-7 and E-12 viruses in September and October 1957 in Osaka area. However, none of the virus carriers and serologically positive cases manifested notable clinical illness, and no epidemic reminded enterovirus infections was found during that period in Osaka.
8) The antibody titers against E-7 virus was compared with those against poliovirus type I on the age specifically pooled sera taken from 602 healthy individuals in Osaka 1955 and 1956. The age which showed higher antibody titers against E-7 was older than that against poliovirus type I, and that the antibody titers of E-7 virus were lower than those of poliovirus type I. Therefore, prevalence of E-7 was considered lower than that of poliovirus type I in the community.
9) The author confirmed from the above experiments that there was widespread inapparent infections of enteroviruses among healthy infants and children in the Japanese urban community, particularly during the summer and early fall.