22 In contrast to the age-month

analysis, age distribution of travelers to specific destinations was not available (Table 1). However, information regarding the increased possibility of contracting various diseases in specific countries should be given to all selleck kinase inhibitor travelers going to these regions. The present study is based on the data covering more than half of the total traveler population entering Japan during the study period. Narita is not that different from other Japanese international airports in terms of proportion of travelers’ age, sex, travel season, and destination.19 Consequently, our results are likely to be representative of the present situation in Japan. Questionnaire distribution and collection and patient consultation are part of the quarantine facility’s daily activities and offered to travelers for free. Therefore, patients with diarrhea presented here are less likely to be affected by any check details financial or insurance-related constraints of the subject.9,10 Additionally, questionnaire forms, data entry management, and database system have not dramatically changed during the

study period. These characteristics are unique for the Narita quarantine station,8 and are the major strengths of this report. However, our study has several limitations. First, our results demonstrated a low response rate and overall incidence of travelers’ diarrhea compared with other studies, in which an incidence ranging from 20% to 50% was reported.4–6,13 Thus, the incidence rates of diarrhea could be biased. There may be some explanations for our lower rate of travelers’ diarrhea. For example, travelers else may have already recovered from the disease on arrival at Narita, and thus did not report its occurrence. In addition, travelers may not have reported their physical problems to save time or to avoid incurring potentially frustrating consequences. Quarantine officers sometimes witness that package tourists have been advised by tour conductors not to submit questionnaire forms

to avoid the possibility of being examined. Self-report bias is difficult to avoid when using current quarantine system.6 Second, some important risk factors, such as type and duration of travel or diet, were not analyzed, as the questionnaire was not structured to collect this information. Since these factors have a marked influence on the incidence of travelers’ diarrhea,1,5,6 this aspect needs to be carefully considered when interpreting results. Third, our data on the incidences of travelers’ diarrhea were not controlled by factors other than the one in question, and therefore, we could not formally identify an independent risk factor for contracting travelers’ diarrhea. Likewise, we need additional studies to clarify age- and/or sex-dependent differences in contracting diarrhea.