Clinical and epidemiological features of acute infantile gastroenteritis associated with human rotavirus subgroups 1 and 2.

During a prospective 1-year study rotavirus isolates from 169 children with gastroenteritis were investigated by polyacrylamide gel electrophoresis. A total of 118 (70%) of the strains analyzed contained sufficient viral nucleic acid to give visible electrophoretic patterns; 36% were identified as strains belonging to subgroup 1 (short patterns), and 64% were identified as strains belonging to subgroup 2 (long patterns). The two subgroups cocirculated at equal frequencies during the first 7 months of the year, after which subgroup 1 rotavirus completely disappeared. Subgroup 2 rotavirus occurred throughout the year. No significant differences between the subgroups in relation to age or sex distribution were observed. Fever and temperatures exceeding 39 degrees C were significantly more frequent in children who shed rotavirus subgroup 1. Diarrhea and vomiting occurred at similar rates in both groups of patients, but were more pronounced in children who shed rotavirus subgroup 2. One of three dominant electropherotypic variants of subgroup 2 rotavirus was found to be associated with more intense symptoms, higher rates of hospitalization, and a significantly higher frequency of respiratory symptoms; the clinical picture may indicate that this rotavirus electropherotype has higher virulence.