Moreover, the study of intestine-microbial interactions which lead to development of HAEC might best be undertaken in the pediatric patient whereby influences of host fecal microbial constituents are more easily elucidated. Therefore, research must not fail to identify other critically important pathogens by too narrow a focus on only known pathogens residing in colonic fecal streams in the genetically susceptible host. In addition, the characterization of gut microflora (i.e., fecal streams) and risk assessment of children with HD can optimally be done with a careful evaluation of both components - host and microbe in the index case. Successfully confirming or disproving infectious hypotheses requires that valid diagnostic tools be employed. Systematic investigations into potential infectious etiologies or normal enteric flora triggers of HAEC, therefore appear biologically plausible, and highly justified.