Role of heat-labile toxigenic Escherichia coli and Reovirus-like agent in diarrhoea in Boston children.

61 Boston children aged five years or less with acute diarrhoea were studied for evidence of infection with Escherichia coli strains that produce heat-labile enterotoxin (L.T.) or with a reovirus-like agent associated with childhood gastroenteritis. This represented the first evaluation of the prevalence of disease produced by these two agents in the same population. E. coli, isolated from acute-phase stool specimens, were tested in adrenal-cell tissue-culture and adult-rabbit ileal-loop assays for L.T. Acute and convalescent phase sera, collected from 31 children, were tested by the adrenal-cell assay for anti-L.T. activity. None of the 61 children demonstrated evidence of infection with L.T.-positive E. coli. Paired sera from 31 of the children studied were also tested for evidence of recent infection with the reovirus-like agent by determining titres of immunofluorescent-staining antibody to the serologically related Nebraska calf diarrhoea virus. 11 of the children (35%) had evidence of recent infection. These results suggest that an important proportion of endemic acute diarrhoea of young children in Boston is caused by the reovirus-like agent, and that disease caused by L.T.-producing E. coli is uncommon.