Persistent high risk of diarrhea among foreigners in Nepal during the first 2 years of residence

Although numerous studies have shown that diarrhea is the most common illne ss occurring during the first few weeks of travel, systematic studies of th e incidence of diarrhea during long-term residence in developing countries have not been performed. We conducted a cohort study of the incidence and e tiology of diarrhea among 77 expatriate adults who had lived in Nepal for < 2 years. Persons were followed prospectively for up to 1 year (mean, 9 mont hs). The incidence of diarrhea during the surveillance period was 3.3 episo des of diarrhea per person per year, or 0.27 episodes per person per month. The annual attack rate of specific pathogens was 42% for enterotoxigenic E scherichia coli, 32% for Cyclospora species, 16% for Giardia lamblia, 16% f or Shigella species, 10% for Campylobacter species, greater than or equal t o 10% for rotavirus, and 6% for Entamoeba histolytica. This study suggests that adult persons from developed countries who move to developing countrie s such as Nepal remain at high risk for diarrhea during their first 2 years of residence.