GASTROINTESTINAL INFECTIONS IN CHILDREN

The World Health Organization estimates that 1.7 x 10(9) episodes of d iarrhea afflict the 4.4 x 10(8) children living in developing countrie s. In the past decade, three quarters of these children now have gaine d access to life-saving oral rehydration salts. The next challenge is to optimize the treatment of persistent diarrhea (> 14 days' duration) for which impaired cell-mediated immunity is a risk factor. New enter opathogens such as picobirnavirus and Cyclospora cayetanensis have app eared and the impact of recently described pathogens such as Cryptospo ridium parvum on child health is being assessed. Established agents su ch as Vibrio cholerae demonstrated their capacity to surprise. The lat ter organism has developed a new serogroup (0139) that displaces the c lassic 01. Immunity to cholera fails to protect, and hence this event may signal the eighth pandemic that has visited the shores of the Unit ed States. The HEp-2 cell adhesion assay has turned up new strains of Escherichia coli on the basis of patterns of adhesion. The search is n ow on to define their precise role in pathogenesis. Enterohemorrhagic E. coli continues to concern us because of its propensity to cause acu te renal failure (hemolytic uremic syndrome) for which there is no spe cific treatment. Increasing problems with antimicrobial therapy have d riven investigators to try new strategies such as oral administration of yeast, which has been shown to be effective against Clostridium dif ficile, the causative agent of antibiotic-associated diarrhea. Nutriti onal therapy remains a cornerstone, and supplementation with soy fiber was shown to hasten the cessation of diarrhea. The role of vitamin A in the prevention of infections is being challenged by reports showing increased risk in supplemented groups.