Studies on the characteristics of Poliovirus type 3. III. Strain characteristics after passage in man.

The markers d, IST, EA1(OH)3 and rct at sub- and supraoptimal temperatures as well as neurovirulence (PMic) for monkeys was determined for strains isolated from children vaccinated with Leon 12a1b vaccine, their contacts and from paralytic cases. The strains were isolated at early and late phases of excretion. The changes concerned mainly rct determined at supraoptimal temperatures, d and PMic markers, especially in strains isolated at the late phase of excretion. The passage through the human alimentary tract did not change such markers as IST and EA1(OH)3. Some degree of correlation was observed between the rct 40.3, d and PMic markers.