A comparative study of 63 strains of ECHO virus type 30.

Abstract

Thirty-three European strains and 30 American strains of ECHO virus type 30 were examined. The strains were representative isolates from 8 distinct outbreaks of infection in various geographical areas between 1959 and 1966. Primary human amnion and WI 38 cells supported the growth of these viruses much more satisfactorily than primary monkey kidney cells. Thirty-one of the total of 63 strains showed haemagglutinating activity with human group 0 erythrocytes. In both neutralization tests in tissue cultures and in haemagglutination inhibition tests the strains showed marked antigenic differences within the serotype. They fell into two broad groups one of which contained the prototype strain. In general, strains isolated in the same outbreak resembled each other, but a few individual strains were antigenically quite unlike other strains from the same outbreak. Antiserum to the Frater strain appears to be capable of neutralizing rather more strains of the virus than antiserum to the prototype. The difference between the prototype strain and the Frater strain is not great. The antigenic variation within the serotype is such that it is unlikely that any single strain is antigenically broad enough to constitute an ideal strain for antiserum production.