Isolation of two enteroviruses, possible "prime" strains of coxsackie A type 17 virus

An application of factor analytics on antigenic drift, and chromatographic analysis on intratypic variation of enterovirus type 70

An attempt was made to reveal the antigenic determinant site of enterovirus (EV) 70 by application of Harman's factor analytics. The normalized neutralization rate constant (NK) values obtained by the kinetic-neutralization tests (NT) with 12 strains of EV70 isolated during the period from 1971 to 1976 were used in the principal factor analysis. From the analytic results, it was suggested that at least two antigenic determinant sites, composing to variable antigenic factor (VAF) and common one (CAF), might be closely related to the antigenic makeup. There were no significant differences in CAF score among the strains, and they were numerically classified into prototype-like and prime-like virus groups from the VAF scores. The drift appeared here could be explained as successive alteration of VAF scores. Chromatographic analyses were carried out on intratypic variable and common particles with two virus strains, i.e. the prototype J 670/71 and prime G-2/74. The intratypic variable and common particles were eluted in low and high ionic concentrations at neutral pH, respectively. It was concluded that the virus populations of two strains were heterogenic in the proportion of variable to common virus particles.

Antigenic analysis of acute hemorrhagic conjunctivitis viruses (enterovirus type 70)

The antigenic characteristics of enterovirus type 70 (EV 70) were investigated by means of cross and kinetic neutralization tests (NT). Twelve strains of EV 70 isolated in a period from 1971 to 1976 were analyzed using seven rabbit and one monkey hyper-immune sera. All the strains investigated were found to possess a common and prime variant antigens in varying proportions. Accordingly, EV 70 isolates were devided intratypically into three antigenic sub groups; (1) prototype-like (four strain from 1971 to 1972), (2) intermediate, G-10/72-like (two strains from 1972 to 1973), and (3) prime variant, G-2/74-like (six strains from 1974 to 1976) groups. Thus it was considered that EV 70 might represent a virus type with antigenic heterogeneity, and that antigenic drift from the prototype to the prime type may have occurred successively after 1971.

Enterovirus infection in a semi-closed community

Infection with enteroviruses was studied over a 61-week period (during 1960-61) in a semi-closed child community in the Detention Home of the Allegheny County Juvenile Court in Pittsburgh, Pennsylvania. While most of the viruses isolated were known adeno- and enterovirus types, three apparently represent new enterovirus types or 'prime strains'. Viruses were isolated in all but 6 weeks of the 61-week study period from the gastro-intestinal tracts of 110 children out of a total population of 514 (21%); of these 110, 24 children (22%) excreted virus at the time of admission. The population averaged 37 children (more than half of whom were under 5 years of age), with a turnover of about nine per week. Spread of infection in this community on introduction of a new virus was demonstrated, with virus shedding of variable duration after infection. Thirteen of the 110 positive children (12%) showed mixed virus infections. During the entire study period, no clinical diarrheal illness was found associated with the viral infections detected.