Abstract
Rotavirus was purified from nine patients hospitalized with acute gastroenteritis from October to December, 1978, in Mexico City. Analysis of their ribonucleic acids by gel electrophoresis showed the presence of two distinct patterns (2s and 22) which had been observed in 1977, but which now were found in a very different proportion: the pattern called 2s, observed in only 11% (6 of 52) of the patients in 1977, was found in 90% (8 of 9) of the patients in 1978. Improvements in the electrophoretic method allowed us to observe differences in the migration of up to seven segments between the two patterns and to distinguish small differences in one or two segments within either of the two ribonucleic acid patterns.