Travelers' diarrhea: an update on susceptibility, prevention, and treatment.

Traditional risk factors do not explain the individual differences in susceptibility to travelers' diarrhea (TD) among the increasing number of travelers to the developing world. Single-nucleotide polymorphisms of the genes encoding for lactoferrin and interleukin 8 (IL-8) have been linked to susceptibility to TD. Subjects with mutations of the FUT2 gene are immune to norovirus infection. The recognition of individual variations in susceptibility to TD will aid in risk stratification of travelers to the developing world. Diagnosis is usually syndromic, but improved diagnostic methods are in development. Quinolones have been the mainstay of antibiotic treatment, but azithromycin (for resistant organisms) and rifaximin (for noninvasive organisms) may provide advantages. Transcutaneous vaccines for the major Escherichia coli enteropathogens are in development. In the future, travel advice, prophylactic medication regimens, and standby treatment for TD will be better tailored to each patient's specific risk factors.