Travelers’ diarrhea remains a prevalent illness impacting individuals visiting developing countries, however most studies have focused on this disease in the context of short term travel. This study aims to determine the regional estimates of travelers’ diarrhea incidence, pathogen-specific prevalence, and describe the morbidity associated with diarrheal disease among deployed military personnel and similar long term travelers. We updated a prior systematic review to include publications between January 1990 and June 2015. Point estimates and confidence intervals of travelers’ diarrhea and pathogen prevalence were combined in a random effects model and assessed for heterogeneity. Eighty-two studies were included in the analysis, including 29 new studies since the prior systematic review. Military personnel were evaluated in 69% of studies and non-military long term travelers in 34%, with a median duration of travel of 4.9 months, and travel predominantly to the Middle East, Southeast Asia, and Latin America and the Caribbean. Sixty-two percent of tested cases were due to bacterial pathogens, with enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), and Campylobacter predominating, and significant regional variability. The incidence of TD from studies with longitudinal data was 36.3 cases per 100 person-months, with the highest rates in Southeast Asia, Latin America and the Caribbean, and the Middle East, with higher estimates from those studies using self-reporting of disease. Morbidity remained significant, with 21% being incapacitated or placed sick in quarters (SIQ) by their illness, 15% requiring intravenous fluids, and 3% requiring hospitalization. In comparison to results from the prior systematic review, there were no significant differences in incidence, pathogen prevalence, or morbidity; however there was a trend toward improved care-seeking by sick individuals.

Background. The US Centers for Disease Control and Prevention estimates 20.9 million norovirus infections annually in the United States. Although the acute disease burden is sizeable, emerging data suggest norovirus may be associated with chronic gastrointestinal problems. We identified known outbreaks in US military recruits and used the Defense Medical Encounter Database (DMED) to identify the risk of new onset functional gastrointestinal disorders (FGD) and gastroesophageal reflux disease (GERD). Methods. Subjects reporting for care of acute gastroenteritis (AGE) at a military treatment clinic during 3 known norovirus outbreaks were identified. Each AGE subject was matched with up to 4 subjects with unrelated medical encounters. Medical encounter data were analyzed for the duration of military service time (or a minimum of 1 year) to assess for incident FGD or GERD. Relative risks were calculated using regression models. Results. We identified 1718 subjects from 3 outbreaks. After controlling for important demographic covariates, the incidence of constipation, dyspepsia, and GERD was approximately 1.5-old higher (P < .01) in AGE-exposed subjects than matched subjects. We also noted variability in outcome incidence across outbreaks. Conclusions. It appears that the risk of dyspepsia, constipation, and GERD are higher among those who have AGE during a confirmed norovirus outbreak. Although these findings need confirmation, they suggest that dysmotility may result subsequent to these infections. If confirmed, the costs and morbidity associated with the chronic consequences of norovirus should be considered.

Background: Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) symptoms often overlap. In some IBS cases there are subtle inflammatory changes similar to the immune-mediated pathophysiology of IBD, and the risk of both increases after infectious gastroenteritis (IGE). Methods: To evaluate the effect of IBS and IGE on IBD risk utilizing US Department of Defense medical encounter data, active duty personnel with IBS were matched to subjects without IBS. Medical encounter history was analyzed to assess for incident IBD. IGE was identified from documented medical encounters and by self-report. Relative risks were calculated using Poisson regression models. Results: We identified 9,341 incident IBS cases and 18,678 matched non-IBS subjects and found an 8.6-fold higher incidence (p < 0.0001) of IBD among those with IBS (238.1 per 100,000 person-years) compared to our referent population (27.8 per 100,000 person-years). In a subset (n = 2,205) of well-defined IBS cases, IBD risk was 15 times that of subjects without IBS. The median time between IBS and IBD diagnoses was 2.1 years. IGE also increased IBD risk approximately 2-fold ( p < 0.05) after controlling for IBS. Conclusions: These data reflect a complex interaction between illness presentation and diagnosis of IBS and IBD and suggest intercurrent IGE may increase IBD risk in IBS patients. Additional studies are needed to determine whether IBS lies on the causal pathway for IBD or whether the two are on a pathophysiological spectrum of the same clinical illness. These data suggest consideration of risk reduction interventions for IGE among IBS patients at high disease risk.