1962 Volume 12 Issue 6 Pages 232-242
The incidence of enterovirus infections has been studied in a total of 58 apparently healthy infants and children under 3 years of age during one year from May 17, 1960 through May 18, 1961, in Takatsuki, Japan.
81 strains (4.7%) of enterovirus and 4 strains of adenovirus were isolated from all 1729 fecal specimens collected about every 10th day.
The monthly isolation rates showed a seasonal prevalence with its peak in August (16.6%), July (12.8%), September (9.9%) and October (7.5%), on the contrary the rates from November to May the next year were as low as 0 to 2 per cent.
The results of identification of the isolated viruses were as follows: Coxsackie B-5 strains were predominantly isolated, i.e., 30 of 53 strains of Coxsakie B viruses isolated were identified as Coxsakie B-5 virus, 13 and 10 viral strains belonged to ECHO and polio virus respectively and 5 strains remained untypable.
The evidence of infection with the enteroviruses were confirmed in 29 persons among all 58 examinees.
Of 29 who were infected with “enteroviruses”, 7 were proved to have been affected with two to five different types of the virus during one year of my study. Coxsackie B virus infections were verified in 24 among those 29 individuals, especially, Coxsackie B-5 infections were predominantly found in 15 persons.
There was no significant difference in the isolation rates by age, so far as my study was concerned.
The duration of virus excretion varied from 10 days to 2 months in polio and ECHO viruses, and from 10 days to 3 months in Coxsackie B-5 virus.
The neutralizing antibody test against Coxsackie B-5 virus was examined on two serum samples taken in May 1960 and January 1961. These 50 examinees gave negative neutralization test against Coxsackie B-5 in the prior sera, except for one who gave positive. 11 individuals of 50 examinees excreted Coxsackie B-5 virus and showed positive conversion of antibody to this virus in the second sera, and one individual showed a rising of the antibody titer but the fecal specimen was not obtained.
A clinical illness was not found in persons whom the enterovirus were recovered in this study. However, the epidemics of aseptic meningitis due to Coxsackie B-5 virus were reported elswhere in the Kansai area during the summer of 1960.
From the above mentioned results, it was confirmed that in Takatsuki not only poliovirus but also Coxsackie B viruses, especially Coxsackie B-5, were prevalent among infants and young children, particularly during the summer of 1960.
When considered the interference-phenomen between heterotypic enteroviruses, it is concluded that the most effective oral vaccination of polio should be performed during the season when the enterovirus infection is considered rare in a temperate zone like Japan.
