Risk and aetiology of diarrhoea at various tourist destinations

Investigating the influence of probiotics in preventing Traveler's diarrhea: Meta-analysis based systematic review

INTRODUCTION

Approximately 10-40 million travelers get Traveler's Diarrhea (TD) yearly. A significant decrease in TD incidence has not been achieved by depending solely on antibiotic prophylaxis and educational initiatives. Using prebiotics to prevent TD has also not been examined in previous evaluations of probiotics for TD, which failed to consider the strain-specificity of probiotic efficacy. This review investigates the overall effects of probiotics on preventing TD, including the impact of dosage, duration, and age.

METHODS

Standard literature databases were searched without restriction on publication year or language. The following criteria are included: randomized controlled trials (RCTs) in English or non-English unrestricted to publication year, excluding animal and observational studies. This systematic review applied the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Of the 166 screened papers, 10 RCTs were included. Lactobacillus acidophilus showed no efficacy in preventing TD except when mixed with other strains. Other genera of lactobacilli showed a protection rate of up to 39% against TD. Similarly, Saccharomyces cerevisiae and Saccharomyces boulardii have been effective in preventing TD.

CONCLUSION

Studies investigating probiotics as a preventive measure for TD remain limited. Only a few probiotics that reduce TD risk exist. Based on this systematic review and meta-analysis, specific probiotic strains, including L. acidophilus, L. rhamnosus, L. fermentum, S. cerevisiae, and S. boulardii, may prevent TD. The effect of additional probiotic strains on TD prevention must be further investigated.

Colonization with extended-spectrum beta-lactamase-producing Escherichia coli and traveler's diarrhea attack rates among travelers to India: a systematic review and meta-analysis

Background

India is an attractive destination for travelers. Unfortunately, numerous reports exist on traveler’s diarrhea (TD) and fecal colonization with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) among international travelers visiting India. Here, we systematically reviewed studies published on the acquisition of ESBL-EC and TD attack rates among international visitors to India.

Methods

Design: Systematic review and meta-analysis.

A systematic search was performed using Google Scholar, PubMed, EMBASE, Web of Science, and gray literature from 2000 to December 2021, for studies containing data for ESBL-EC acquisition or TD experience related to a trip to India. Random effects models were used to compute the prevalence of ESBL-EC acquisition and TD attack.

Results

The literature search yielded a total of 5023 records. Of these, 31 met our inclusion criteria for systematic review and only 17 could be meta-analyzed (9 for TD, and 8 for ESBL-EC). The overall pooled attack rate of TD was 39% (95% confidence interval, CI: 25–53%). In studies where travelers' memory was used to diagnose TD, the pooled attack rate of TD was slightly higher (42%, 95% CI: 21–64%) compared to those where TD was objectively documented (33%, 95% CI: 17–49%). There were significant risks to be colonized with ESBL-EC among the travelers who experienced TD. The pooled rate of ESBL-EC colonization was 72% (CI: 67–78%). Most ESBL-EC produced CTX-M-15 enzyme. Furthermore, most of the travelers who acquired ESBL-EC were from highly industrialized countries recruited from travel clinics: Canada (n = 80), Germany (n = 69), Netherlands (n = 20), Sweden (n = 18), Japan (n = 10), Finland (n = 8), USA (n = 7), Spain (n = 5), and Denmark (n = 3).

Conclusions

TD pooled attack rate and ESBL-EC acquisition among international travelers visiting India were high in this study. However, we cannot make generalizations based upon this TD pooled attack rate for the current situation, due to a lack of current data. Our study highlights that travelers should be advised on TD to ensure that they do not disregard the risk of contracting TD and be better prepared as a result. It also illustrates the importance of international travel in acquiring antibiotic-resistant Escherichia coli.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40794-022-00179-1.

Bacterial travellers' diarrhoea: A narrative review of literature published over the past 10 years

Travellers' diarrhoea (TD) is the most frequent illness experienced by international travellers to lower-income countries with bacterial agents considered to account for 80-90% of cases. In this review, we summarise evidence published on bacterial TD over the past 10 years, focusing on the epidemiology and aetiology of TD. Diarrhoeagenic Escherichia coli (DEC) continue to be the most commonly implicated bacteria in TD, although Enteropathogenic E. coli (EPEC) and Enteroaggregative E. coli (EAEC) now appear to be predominant where Enterotoxigenic E. coli (ETEC) was previously considered most prevalent globally. Where fluroquinolone resistance had primarily been documented for Campylobacter in Southeast Asia, widespread resistance has been observed in most regions of the world for multiple enteropathogens, including Shigella, Salmonella, ETEC and EAEC. Implementation of novel molecular methods for pathogen detection has led to identification of bacterial pathogens, including Clostridium difficile (with and without the use of prior antibiotics), Arcobacter species and Bacteroides fragilis, as aetiological agents in TD. The widespread resistance to first-line antibiotics in multiple bacterial enteropathogens warrants continued surveillance and re-evaluation of current treatment practices. Further investigations are required to determine the prevalence and geographical distribution of bacterial enteropathogens that have been more recently implicated in TD.

Intestinal colonization with extended-spectrum beta-lactamase producing Enterobacterales (ESBL-PE) during long distance travel: A cohort study in a German travel clinic (2016-2017)

BACKGROUND

Intercontinental travel contributes to the spread of extended-spectrum beta-lactamase producing Enterobacterales (ESBL-PE). We assessed risk factors for intestinal ESBL-PE colonization in people travelling to low and middle income countries in the tropics and subtropics to better understand how travel affects ESBL-PE spread.

METHOD

This prospective cohort study in travellers attending a travel clinic in Leipzig, Germany was conducted in 2016-2017. Information on risk factors related to travel, symptoms, antibiotic use, health care usage, accommodation, destination, diet and hygiene was collected by questionnaire after travel. Stools were phenotypically tested for ESBL-PE before and after travel. Risk factors for ESBL-PE colonization were identified using logistic regression.

RESULTS

Of the 230 travellers that were ESBL-PE negative before travelling, 23% (n = 53) travellers returned positive. Multivariable analyses showed that age, type of accommodation and travelling to Asia were associated with ESBL-PE colonization.

CONCLUSIONS

Given that a considerable amount of travellers returned with ESBL-PE, we recommend raising awareness in returning high-risk travellers, e.g. those returning from high-risk areas. They should be aware that they may carry antimicrobial-resistant bacteria after travel, and how they can prevent its spread. The role of the type of accommodation as a factor favouring intestinal colonization with ESBL-PE requires further investigation.

A Review of Guidelines/Guidance from Various Countries Around the World for the Prevention and Management of Travellers' Diarrhoea: A Pharmacist's Perspective

International travel is growing and pharmacists are well placed to provide travel health services for the prevention and management of travellers’ diarrhoea (TD). Legislation changes in many countries has enabled pharmacists to access prescription only medicines and vaccinations to provide advice and over the counter medicines for the prevention and management for travel health services; this makes sense since pharmacies are easily accessible to the public and are the patient’s first port of call in the event of any illness. Currently, whilst many guidelines/guidance exist worldwide for the prevention and management of TD, there is no review that focuses on similarities and differences between these and between guidelines on TD and travel related and non-travel related acute diarrhoea. There is also a lack of publication on legislation and the need for evidence based training for all prescribers to provide travel health services. The aims of this work were to review guidelines/guidance for the prevention and management of TD from across the world which were compared with each other as were the TD guidelines compared to that for travel related and non-travel related acute diarrhoea for similarities and differences, with a focus on any relevant pharmacy legislation, needs assessments and training that may impact upon provision of travel health services by pharmacists focusing mainly on TD in adults. The PubMed, Google Scholar and Cochrane database were used to carry out an online search for publications on TD, acute diarrhoea and the guidance pharmacists have in the prevention and management of diarrhoea. The literature reviewed in this article indicates that where no specific guidelines/guidance existed, some pharmacists used the WHO guidelines (WHO), highlighting a need for local, regional and national evidence based guidelines in these countries.

Prospective study evaluating immune-mediated mechanisms and predisposing factors underlying persistent postinfectious abdominal complaints

BACKGROUND

The role of persistent immune activation in postinfectious irritable bowel syndrome (PI-IBS) remains controversial. Here, we prospectively studied healthy subjects traveling to destinations with a high-risk to develop infectious gastroenteritis (IGE) in order to identify immune-mediated mechanisms and risk factors of PI-IBS.

METHODS

One hundred and one travelers were asked to complete questionnaires on psychological profile and gastrointestinal (GI) symptoms before travel, 2 weeks, 6 months and 1 year after travel. At each visit, blood was collected for PBMC isolation and rectal biopsies were taken. PI-IBS was diagnosed using the Rome III criteria and subjects with persistent postinfectious abdominal complaints (PI-AC) were identified using 3 GSRS symptoms (ie, loose stools, urgency and abdominal pain).

RESULTS

Forty-seven of the 101 subjects reported IGE during travel. After 1 year, two subjects were diagnosed with PI-IBS and eight subjects were presented with PI-AC versus two subjects with IBS and two with abdominal complaints in the non-infected group. PBMC analysis showed no differences in T and B cell populations in subjects with PI-AC vs healthy. Additionally, no differences in gene expression were observed in the early postinfectious phase or after 1 year. Regression analysis identified looser stools, higher anxiety and somatization before infection and several postinfectious GI symptoms as risk factors for PI-AC.

CONCLUSIONS

The incidence of PI-IBS is low following travelers' diarrhea and there is need for larger studies investigating the role of immune activation in PI-IBS. Psychological factors before infection and the severity of symptoms shortly after infection are risk factors for the persistence of PI-AC.

A Novel mcr-1 Variant Carried by an IncI2-Type Plasmid Identified From a Multidrug Resistant Enterotoxigenic Escherichia coli

In this study, we discovered a novel mobilized colistin resistance (mcr-1) gene variant, named mcr-1.9, which was identified in a colistin-resistant enterotoxigenic Escherichia coli (ETEC) strain from a clinical diarrhea case. The mcr-1.9 gene differs from mcr-1 at position 1036 due to a single nucleotide polymorphism (G→A), which results in an aspartic acid residue being replaced by an asparagine residue (Asp346→Asn) in the MCR-1 protein sequence. Antimicrobial susceptibility testing showed that the mcr-1.9-harboring ETEC strain is resistant to colistin at a minimum inhibitory concentration of 4 μg/ml. Plasmid profiling and conjugation experiments also suggest that the mcr-1.9 variant can be successfully transferred into the E. coli strain J53, indicating that the gene is located on a transferable plasmid. Bioinformatics analysis of data obtained from genome sequencing indicates that the mcr-1.9 gene is located on a 64,005 bp plasmid which has been named pEC26. This plasmid was found to have high similarity to the mcr-1-bearing IncI2-type plasmids pWF-5-19C (99% identity and 99% coverage) and pmcr1-IncI2 (99% identity and 98% coverage). The mcr-1.9-harboring ETEC also shows multidrug resistance to nine classes of antibiotics, and contains several virulence and antimicrobial-resistance genes suggested by the genome sequence analysis. Our report is the first to identify a new mcr-1 variant in an ETEC isolated from a human fecal sample, raising concerns about the existence of more such variants in human intestinal flora. Therefore, we believe that an undertaking to identify new mcr-1 variants in the bacterial communities of human intestines is of utmost importance, and that measures need to be taken to control the spread of mcr-1 and its variants in human intestinal microflora.

Travellers' diarrhoea: Impact of TD definition and control group design on study results

BACKGROUND

Travellers' diarrhoea (TD) is a common health problem among visitors to the (sub)tropics. Much research deals with aetiology, prevention, and post-infection sequalae, yet the data may not allow comparisons due to incompatible definitions of TD and No TD control groups.

METHOD

The impact of defining TD and No TD control groups was explored by revisiting our recent data. We set up two TD groups: classical TD i.e. ≥3 loose or liquid stools/day and WHO TD (diarrhoea as defined by the WHO) i.e. any diarrhoea, and four No TD groups by TD definition and timing (no classical/WHO TD during travel, no ongoing classical/WHO TD).

RESULTS

TD was recorded for 37% versus 65% of subjects when using classical versus WHO definitions, respectively; the proportions of the various pathogens proved similar. The strictest criterion for the No TD control group (no WHO TD during travel) yielded pathogens among 61% and the least strict (no ongoing classical TD) among 73% of the travellers; the differences were greatest for enteroaggregative Escherichia coli and Campylobacter.

CONCLUSIONS

Definition of TD and control group design substantially impact on TD study results. The WHO definition yields more cases, but the pathogen selection is similar by both definitions. Design of the No TD control group was found critical: only those remaining asymptomatic throughout the journey should be included.

Incidence and spectrum of health problems among travellers to Myanmar

BACKGROUND

The number of international travellers visiting Myanmar increases each year. However, information about pre-travel preparation and incidence of health problems among these travellers is limited.

METHODS

This cross-sectional study was conducted at three international airports in Thailand. Travellers returning from Myanmar completed questionnaires querying demographic profile, pre-travel health preparations and health problems during their stay in Myanmar.

RESULTS

From March 2015 to May 2017, we collected and analysed questionnaires completed by 397 Thai and 467 non-Thai travellers (total: 50.1% men, median age 37 years). Non-Thai travellers were from Europe (59%), Northern America (21.4%), Asia (16.5%) and Australia or New Zealand (3.0%). Approximately 74% of non-Thais sought pre-travel health information; only 36% of Thais did so. Tourism was the main purpose for travel among both Thais (58.4%) and non-Thais (85.2%). Non-Thais were more likely than Thais to travel as backpackers and perform outdoor activities such as trekking, cycling or swimming. The average length of stay in Myanmar among non-Thais was significantly longer than that of Thais (26.58 days vs 7.08 days, P < 0.001). Health problems were reported by 22.9% of non-Thais; the most common was diarrhoea (21.0%) followed by upper respiratory tract symptoms (9.2%), fever (3.4%) and skin problems (3.0%). Only 12.6% of Thais reported health problems, the most common being upper respiratory tract symptoms (7.6%), followed by diarrhoea (3.1%), fever (2.8%) and skin problems (2.0%). Most health problems were mild and self-limited in both groups. Only one Thai and eight non-Thai travellers required a doctor's visit during their trip to Myanmar, and two non-Thais required hospitalization.

CONCLUSIONS

Health problems are not very common among travellers to Myanmar. Overall, health problems were reported among 18.2% of travellers in our study. Most problems were mild, with spontaneous recovery. Only two foreign travellers required hospitalization.

Health problems among Thai tourists returning from India

BACKGROUND

The number of Thai tourists visiting India is increasing each year. Most studies investigating health problems among international travellers to India have focused on travellers from Europe or North America, and the applicability of these studies to Asian travellers is unknown.

METHODS

This cross-sectional study used data collected from Thai tourists who had recently completed a trip to India. A questionnaire on demographic data, travel characteristics, pre-travel health preparation, and health problems during the trip to India was administered. All participants were also invited to answer a follow-up questionnaire 15 days after their arrival.

RESULTS

The study included 1,304 Thai tourists returning from India between October 2014 and March 2015. Sixty-two percent were female. Overall median age was 49 years, and the median length of stay was 10.6 days. Most were package tourists, and 52% (675) reported health problems during their trip. Common health problems were cough, runny nose, and sore throat (31.1%), followed by musculoskeletal problems (21.7%), fever (12.7%), diarrhea (9.8%) and skin problems (6.6%). Other reported problems were related to the eyes/ears (2.1%), animal exposure (1.9%) and accidents (0.8%). We found that several factors may be associated with the incidence of health problems among these tourists, including travelling style and travel health preparation. In the follow-up questionnaire, 16.8% of the participants reported new or additional symptoms that developed after their return to Thailand. Respiratory symptoms were still the most common health problems during this 15-day period.

CONCLUSIONS

Over half (52%) of Thai tourists experienced health problems during their trip to India. The most common health problem was not travellers' diarrhoea, as would be expected from published studies. Rather, respiratory and musculoskeletal problems were common symptoms. This information will be useful in pre-travel assessment and care. Our findings may indicate that health risks among travellers vary by nationality.

Travelers' Diarrhea and Other Gastrointestinal Symptoms Among Boston-Area International Travelers

AbstractThis prospective cohort study describes travelers' diarrhea (TD) and non-TD gastrointestinal (GI) symptoms among international travelers from the Boston area, the association of TD with traveler characteristics and dietary practices, use of prescribed antidiarrheal medications, and the impact of TD and non-TD GI symptoms on planned activities during and after travel. We included adults who received a pre-travel consultation at three Boston-area travel clinics and who completed a three-part survey: pre-travel, during travel, and post-travel (2-4 weeks after return). TD was defined as self-reported diarrhea with or without nausea/vomiting, abdominal pain, or fever. Demographic and travel characteristics were evaluated by χ2 test for categorical and Wilcoxon rank-sum test for continuous variables. Analysis of dietary practices used logistic generalized estimating equation models or logistic regression models. Of 628 travelers, 208 (33%) experienced TD and 45 (7%) experienced non-TD GI symptoms. Of 208 with TD, 128 (64%), 71 (36%), and 123 (62%) were prescribed ciprofloxacin, azithromycin, and/or loperamide before travel, respectively. Thirty-nine (36%) of 108 took ciprofloxacin, 20 (38%) of 55 took azithromycin, and 28 (28%) of 99 took loperamide during travel. Of 172 with TD during travel, 24% stopped planned activities, and 2% were hospitalized. Of 31 with non-TD GI symptoms during travel, six (13%) stopped planned activities. International travelers continue to experience diarrhea and other GI symptoms, resulting in disruption of planned activities and healthcare visits for some. Although these illnesses resulted in interruption of travel plans, a relatively small proportion took prescribed antibiotics.

'Holiday sickness'-reported exploratory outcome of over 500 United Kingdom holidaymakers with travellers' diarrhoea

AIMS

To ascertain any predictors of potential food poisoning pathogens and development of post-infective irritable bowel syndrome (IBS) in UK travellers. An analysis was undertaken on prospectively collected data on 527 patients reporting symptoms of suspected food poisoning between June 2012 and June 2015.

MAIN OUTCOME MEASURES

Positive stool sample indicative of food poisoning pathogens and diagnosis of post-infective IBS.

RESULTS

Data on 527 patients were examined. The large majority of patients did not provide a stool sample on return from holiday (n = 430, 81.6%) as few visited a Doctor locally or in the UK. Only 18 patients (18.6%, 95% confidence interval [CI] 11.4-27.7) who provided a stool sample were positive for microbiological food poisoning pathogens. Univariate analysis indicated a significant relationship between a positive stool sample and whether the individual sought any medical assistance at the resort (odds ratio [OR] 0.24, 95% CI 0.08-0.70) and whether they took any treatment (including self-medicated), (OR 0.21, 95% CI 0.06-0.67). Of the 527 patients only 30 (5.7%, 95% CI 3.9-8.1) experienced post-infective IBS. Univariate regression indicated a significant relationship between experiencing Per Rectal (PR) bleeding and a diagnosis of post-infective IBS (OR 3.64, 95% CI 1.00-10.49). Univariate regression also indicated an increase in the risk of developing post-infective IBS with increasing duration of symptoms (OR 1.04, 95% CI 1.02-1.05). No significant relationship was found between a positive stool sample and developing post-infective IBS (P = 0.307).

CONCLUSIONS

Very few patients provide a stool sample after experiencing holiday sickness abroad. Of those that do, only a small proportion have a positive stool sample indicative of a food poisoning microorganism. Around 6% of individuals were diagnosed with post-infective IBS. Those individuals with PR bleeding and symptoms persisting for longer durations were significantly more at risk of developing post-infective IBS, whilst medical aid and treatment abroad was found to reduce the odds of a positive stool sample.

Comparison of Two Forms of Loperamide-Simeticone and a Probiotic Yeast (Saccharomyces boulardii) in the Treatment of Acute Diarrhoea in Adults: A Randomised Non-Inferiority Clinical Trial

BACKGROUND

Acute diarrhoea is a frequent health problem in both travellers and residents that has a social and economic impact. This study compared the efficacy and tolerability of two loperamide-simeticone formulations and a Saccharomyces boulardii capsule as symptomatic treatment.

METHODS

This was a prospective, randomised, single (investigator)-blind, three-arm, parallel group, non-inferiority clinical trial in adult subjects with acute diarrhoea at clinics in Mexico and India, with allocation to a loperamide-simeticone 2/125 mg caplet or chewable tablet (maximum eight in 48 h) or S. boulardii (250 mg twice daily for 5 days).

OUTCOME MEASURES

The primary outcome measure was the number of unformed stools between 0 and 24 h following the initial dose of study medication (NUS 0-24). The secondary outcome measures were time to last unformed stool (TLUS), time to complete relief of diarrhoea (TCRD), time to complete relief of abdominal discomfort (TCRAD) and the subject's evaluation of treatment effectiveness. Follow-up endpoints at 7 days were feeling of complete wellness; stool passed since final study visit; and continued or recurrent diarrhoea.

SUBJECTS

In this study, 415 subjects were randomised to either a loperamide-simeticone caplet (n = 139), loperamide-simeticone chewable tablet (n = 139) or S. boulardii capsule (n = 137) and were included in the intention-to-treat analysis.

RESULTS

With regards to mean NUS 0-24, the loperamide-simeticone caplet was non-inferior to loperamide-simeticone tablets (3.4 vs. 3.3; one-sided 97.5 % confidence interval ≤0.5), with both significantly lower than S. boulardii (4.3; p < 0.001). The loperamide-simeticone groups had a shorter median TLUS [14.9 and 14.0 vs. 28.5 h (loperamide-simeticone caplet and chewable tablet groups, respectively, vs. S. boulardii); p < 0.001], TCRD (26.0 and 26.0 vs. 45.8 h; p < 0.001) and TCRAD (12.2 and 12.0 vs. 23.9 h; p < 0.005) than S. boulardii. Treatment effectiveness for overall illness, diarrhoea and abdominal discomfort relief was greater (p < 0.001) in the loperamide-simeticone groups than with S. boulardii. At 7-day follow-up most subjects reported passing stool at least once since the final study visit (loperamide-simeticone caplet 94.1 %, loperamide-simeticone chewable tablet 94.8 %, S. boulardii 97.0 %), did not experience continued or recurrent diarrhoea [loperamide-simeticone caplet 3.7 % (p < 0.03 vs. S. boulardii), loperamide-simeticone chewable tablet 3.7 %, S. boulardii 5.7 %] and felt completely well [loperamide-simeticone caplet 96.3 % (p < 0.02 vs. S. boulardii), loperamide-simeticone chewable tablet 96.3 % (p < 0.02 vs. S. boulardii), S. boulardii 88.6 %]. All treatments were well-tolerated with few adverse events.

CONCLUSIONS

The loperamide-simeticone caplet was non-inferior to the original loperamide-simeticone chewable tablet formulation; both formulations can be expected to demonstrate similar clinical efficacy in the relief of symptoms of acute diarrhoea. Both loperamide-simeticone formulations were superior to the S. boulardii capsule in the primary and secondary endpoints.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT00807326.

Psychological comorbidity increases the risk for postinfectious IBS partly by enhanced susceptibility to develop infectious gastroenteritis

OBJECTIVE

Psychological factors increase the risk to develop postinfectious IBS (PI-IBS), but the mechanisms involved are unclear. As stress affects the immune system, we investigated the potential interaction between psychological factors, the immune response against infectious gastroenteritis (IGE) and the development of IGE and PI-IBS in a large cohort exposed to contaminated drinking water.

DESIGN

18 620 people exposed to contaminated drinking water (norovirus, Giardia lamblia, Campylobacter jejuni) were invited to participate in a prospective controlled cohort study. They were asked to complete questionnaires assessing demographic, psychological and clinical data during the outbreak and 1 year later. At both time points, in-depth immune function (peripheral blood and rectal biopsies) was studied in a subgroup of subjects.

RESULTS

1379 subjects completed the questionnaires during the outbreak, of which 271 developed IGE. Risk factors for IGE included younger age, pre-existing dyspepsia-like symptoms, anxiety and drinking contaminated tap water. Anxiety scores before the outbreak inversely correlated with interleukin-2-expressing CD4+ T cells (r=0.6, p=0.01, n=23). At follow-up, 34 of 172 (20%) IGE subjects developed IBS compared with 24/366 exposed participants (7%, p<0.0001, χ(2) test). A Th2 cytokine phenotype at time of infection was associated with increased risk for PI-IBS 1 year later. Except for increased B cell numbers, no evidence for systemic or rectal mucosal immune activation in PI-IBS was demonstrated at follow-up.

CONCLUSIONS

Our study shows that the increased risk of patients with psychological comorbidity to develop PI-IBS may partly result from an increased susceptibility to develop IGE, possibly resulting from a Th2-immune bias.

TRIAL REGISTRATION NUMBER

(ClinicalTrials.gov NCT01497847).

Traveler's Diarrhea

Traveler's diarrhea (TD) is the most common travel-related illness, and it can have a significant impact on the traveler. Pretravel consultation provides an excellent opportunity for the clinician to counsel the traveler and discuss strategies such as food and water hygiene, vaccinations, and medications for prophylaxis or self-treatment that may decrease the incidence and impact of TD. Postinfectious sequelae, such as postinfectious irritable bowel syndrome, reactive arthritis, and Guillain-Barre syndrome, may develop weeks or months after return.

Traveling with children: beyond car seat safety

OBJECTIVE

To spread knowledge and instigate the health professional to give advice on childcare during travels and on child transport safety.

SOURCES OF DATA

Literature review through the LILACS and MEDLINE(®) databases, using the terms: travel, safety, protective equipment, child, preventive medicine, retrieving articles published in the last 21 years.

SUMMARY OF THE FINDINGS

The authors analyzed 93 articles, of which 66 met the inclusion criteria after summaries were read. For drafting this article, the following sub-themes were proposed: getting ready to travel with children; knowing some of the transfer risks (air, land and water transportation) and exploring the destination with children (sun exposure, accommodations, altitude, food, traveler's diarrhea, insect bites) and return from the trip with children.

CONCLUSIONS

Over the years, there has been an increase in the number of children who travel around the world. However, this population is still subject to health problems while traveling and may be even more susceptible than the adult age group. These problems arise from a variety of factors, including exposure to infectious organisms, the use of certain types of transportation, and participation in some activities, such as hiking at high altitudes, among others. However, when traveling with children, these risk factors can be overlooked; a trip that is considered safe for an adult might not be a good choice for this age group. The pediatric consultation should be a good opportunity to optimize preventive guidelines at the pre-trip planning.

Enteric Bacteria Isolated from Diarrheal Patients in Korea in 2014

OBJECTIVES

The aim of this study was to characterize the pathogens responsible for causing diarrhea according to season, region of isolation, patient age, and sex as well as to provide useful data for the prevention of diarrheal disease.

METHODS

Stool specimens from 14,886 patients with diarrhea were collected to identify pathogenic bacteria from January 2014 to December 2014 in Korea. A total of 3,526 pathogenic bacteria were isolated and analyzed according to season, region of isolation, and the age and sex of the patient.

RESULTS

The breakdown of the isolated pathogenic bacteria were as follows: Salmonella spp. 476 (13.5%), pathogenic Escherichia coli 777 (22.0%), Vibrio parahaemolyticus 26 (0.74%), Shigella spp. 13 (0.37%), Campylobacter spp. 215 (6.10%), Clostridium perfringens 508 (14.4%), Staphylococcus aureus 1,144 (32.4%), Bacillus cereus 356 (10.1%), Listeria monocytogenes 1 (0.03%), and Yersinia enterocolitica 10 (0.3%). The isolation rate trend showed the highest ratio in the summer season from June to September for most of the pathogenic bacteria except the Gram-positive bacteria. The isolation rate of most of the pathogenic bacteria by patient age showed highest ratio in the 0-19 year age range. For isolation rate by region, 56.2% were isolated from cities and 43.8% were isolated from provinces.

CONCLUSION

Hygiene education should be addressed for diarrheal disease-susceptible groups, such as those younger than 10 years, aged 10-19 years, and older than 70 years, and monitoring for the pathogens is still required. In addition, an efficient laboratory surveillance system for infection control should be continued.

Epidemiology and self-treatment of travelers' diarrhea in a large, prospective cohort of department of defense beneficiaries

BACKGROUND

Infectious diarrhea is a common problem among travelers. Expert guidelines recommend the prompt use of antibiotics for self-treatment of moderate or severe travelers' diarrhea (TD). There is limited data on whether travelers follow these self-treatment guidelines. We evaluated the risk factors associated with TD, the use of TD self-treatment, and the risk of irritable bowel syndrome (IBS) during travel.

METHODS

Department of Defense beneficiaries traveling outside the United States for ≤6.5 months were enrolled in a prospective cohort study. Participants received pre- and post-travel surveys, and could opt into a travel illness diary and follow-up surveys for symptoms of IBS. Standard definitions were used to assess for TD and IBS. Suboptimal self-treatment was defined as the use of antibiotics (with or without antidiarrheal agents) for mild TD, or the use of antidiarrheals alone or no self-treatment in cases of moderate or severe TD.

RESULTS

Twenty-four percent of participants (270/1,120) met the criteria for TD. The highest incidence was recorded in Africa [8.6 cases/100 person-weeks, 95% confidence interval (CI): 6.7-10.5]. Two hundred and twelve participants with TD provided information regarding severity and self-treatment: 89 (42%) had mild TD and 123 (58%) had moderate or severe TD. Moderate or severe TD was independently associated with suboptimal self-treatment [OR 10.4 (95% CI: 4.92-22.0)]. Time to last unformed stool did not differ between optimal and suboptimal self-treatment. IBS occurred in 4.5% (7/154) of TD cases and in 3.1% (16/516) of cases without TD (p = 0.39). Among TD cases, a lower incidence of IBS was noted in participants who took antibiotics [4.8% (5/105) vs 2.2% (1/46)] in those who did not, but the difference did not reach statistical significance (p = 0.60).

CONCLUSIONS

Our results suggest the underutilization of antibiotics in travelers with moderate or severe TD. Further studies are needed to systematically evaluate pre-travel instruction and traveler adherence to self-treatment guidelines, and the impact of suboptimal self-treatment on outcomes.

Therapy of acute gastroenteritis: role of antibiotics

Acute infectious diarrhoea remains a very common health problem, even in the industrialized world. One of the dilemmas in assessing patients with acute diarrhoea is deciding when to test for aetiological agents and when to initiate antimicrobial therapy. The management and therapy of acute gastroenteritis is discussed in two epidemiological settings: community-acquired diarrhoea and travellers' diarrhoea. Antibiotic therapy is not required in most patients with acute gastroenteritis, because the illness is usually self-limiting. Antimicrobial therapy can also lead to adverse events, and unnecessary treatments add to resistance development. Nevertheless, empirical antimicrobial therapy can be necessary in certain situations, such as patients with febrile diarrhoeal illness, with fever and bloody diarrhoea, symptoms persisting for >1 week, or immunocompromised status.

Diarrheal illness among US residents providing medical services in Haiti during the cholera epidemic, 2010 to 2011

Although nosocomial transmission of cholera is rare, two US healthcare workers (HCW) became ill with cholera after providing medical services during the Haiti cholera epidemic. To assess the incidence of diarrheal illness and explore preventive health behaviors practiced by US residents who provided medical services in Haiti, we conducted a cross-sectional, anonymous, web-based survey. We e-mailed 896 participants from 50 US-based, health-focused non-governmental organizations (NGOs), of whom 381 (43%) completed the survey. Fifty-six percent of respondents (n = 215) reported providing some care for patients with cholera. Diarrhea was reported by 31 (8%) respondents. One person was diagnosed with cholera by serologic testing. NGOs responding to international emergencies should ensure ample access to basic hygiene supplies and should promote their use to reduce the incidence of diarrheal illness among HCW working overseas.

Effectiveness of rifaximin in prevention of diarrhoea in individuals travelling to south and southeast Asia: a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Travellers' diarrhoea causes substantial acute and long-term morbidity. Chemoprophylaxis with fluoroquinolones or rifaximin is effective in prevention of diarrhoea in individuals travelling to Latin America and Africa. Little evidence is available to support the protective effect of antimicrobial drugs in south and southeast Asia, where enteroinvasive and antibiotic-resistant bacteria cause a substantial proportion of diarrhoeal episodes. We aimed to assess the effectiveness of rifaximin in prevention of diarrhoea in individuals travelling to south and southeast Asia.

METHODS

We did this double-blind, placebo-controlled, single-centre, parallel-group, clinical trial in Tübingen, Germany, between Nov 12, 2009, and Sept 3, 2012. Individuals aged 18-64 years who were planning a 6-28 day journey to south and southeast Asia were randomly assigned (1:1), according to a randomisation list (permuted block size of eight) generated by an independent statistician, to receive placebo or rifaximin 200 mg tablets twice daily. All members of the study team, including investigators, those assessing outcomes, and data analysts, were masked to treatment allocation. The primary endpoint was time to the first episode of classic travellers' diarrhoea, defined as three or more loose stools in 24 h, accompanied by one or more enteric symptoms. Analyses were by intention to treat and per protocol.

FINDINGS

We randomly assigned 258 participants to rifaximin (n=129) or placebo (n=129), of whom 239 (93%) returned a completed diary and were included in the primary effectiveness analysis. 48 (41%) of 117 participants in the placebo group and 30 (25%) of 122 in the rifaximin group reported classic episodes of travellers' diarrhoea. From departure to 7 days after return, rifaximin provided 48% protection (95% CI 16-68) by lowering the incidence of travellers' diarrhoea from 1·99 (1·50-2·64) per 100 person-days in the placebo group to 1·04 (0·72-1·48) in the intervention group (incidence rate ratio 0·52, 95% CI 0·32-0·84; p=0·005). The number needed to treat was 5·70 (95% CI 3·44-16·69) to prevent one case of classic travellers' diarrhoea during the first 3 weeks of follow-up. The per-protocol analysis essentially corroborated the findings from the intention-to-treat analysis. We recorded one serious adverse event in a participant in the rifaximin group who had grade 3 right lower quadrant abdominal pain 72 h after the last intake of study drug. The complaints were considered unlikely to be related to use of the drug.

INTERPRETATION

Rifaximin is moderately effective in prevention of diarrhoea in individuals travelling to south and southeast Asia. Similar studies are needed to inform travellers and practitioners about the effectiveness of this drug at other popular destinations.

Traveler's Diarrhea

Travelers' diarrhea (TD) is the most important health issue among international travelers. In high risk areas, 50-90% of travelers may experience an episode of TD. The risk of acquiring TD is influenced by factors such as the destination, duration of stay, standard of accommodation, type of travel, age of the traveler, and also by individual risk factors. Most cases of TD are caused by bacteria; treatment for TD are loperamide and antibiotics. Preventive strategies such as hygiene measures have limited impact. Prophylactic intake of antibiotics or vaccines to prevent from TD can be considered in special situations.

Travel-associated enteric infections diagnosed after return to the United States, Foodborne Diseases Active Surveillance Network (FoodNet), 2004-2009

BACKGROUND

Approximately 40% of US travelers to less developed countries experience diarrheal illness. Using data from the Foodborne Diseases Active Surveillance Network (FoodNet), we describe travel-associated enteric infections during 2004-2009, characterizing the patients, pathogens, and destinations involved.

METHODS

FoodNet conducts active surveillance at 10 US sites for laboratory-confirmed infections with 9 pathogens transmitted commonly through food. Travel-associated infections are infections diagnosed in the United States but likely acquired abroad based on a pathogen-specific time window between return from international travel to diagnosis. We compare the demographic, clinical, and exposure-related characteristics of travelers with those of nontravelers and estimate the risk of travel-associated infections by destination, using US Department of Commerce data.

RESULTS

Of 64,039 enteric infections reported to FoodNet with information about travel, 8270 (13%) were travel associated. The pathogens identified most commonly in travelers were Campylobacter (42%), nontyphoidal Salmonella (32%), and Shigella (13%). The most common travel destinations were Mexico, India, Peru, Dominican Republic, and Jamaica. Most travel-associated infections occurred in travelers returning from Latin America and the Caribbean (LAC). Risk was greatest after travel to Africa (75.9 cases per 100,000 population), followed by Asia (22.7 cases per 100,000), and LAC (20.0 cases per 100,000).

CONCLUSIONS

The Latin America and Caribbean region accounts for most travel-associated enteric infections diagnosed in the United States, although travel to Africa carries the greatest risk. Although FoodNet surveillance does not cover enterotoxigenic Escherichia coli, a common travel-associated infection, this information about other key enteric pathogens can be used by travelers and clinicians in pre- and posttravel consultations.

Diarrhea outbreak during U.S. military training in El Salvador

Infectious diarrhea remains a major risk to deployed military units worldwide in addition to their impact on travelers and populations living in the developing world. This report describes an outbreak of diarrheal illness in the U.S. military’s 130^th Maneuver Enhancement Brigade deployed in San Vicente, El Salvador during a training and humanitarian assistance mission. An outbreak investigation team from U.S. Naval Medical Research Unit – Six conducted an epidemiologic survey and environmental assessment, patient interviews, and collected stool samples for analysis in an at risk population of 287 personnel from May 31^st to June 3^rd, 2011. Personnel (n = 241) completed an epidemiological survey (87% response rate) and 67 (27%) reported diarrhea and/or vomiting during the past two weeks. The median duration of illness was reported to be 3 days (IQR 2–4 days) and abdominal pain was reported among 30 (49%) individuals. Presentation to the medical aid station was sought by (62%) individuals and 9 (15%) had to stop or significantly reduce work for at least one day. Microscopy and PCR analysis of 14 stool samples collected from previously symptomatic patients, Shigella (7), Cryptosporidium (5), and Cyclospora (4) were the most prevalent pathogens detected. Consumption of food from on-base local vendors (RR = 4.01, 95% CI = 1.53–10.5, p-value <0.001) and arriving on base within the past two weeks (RR = 2.79, 95% confidence [CI] = 1.35–5.76, p-value = 0.001) were associated with increased risk of developing diarrheal disease. The risk of infectious diarrhea is great among reserve military personnel during two week training exercises. The consumption of local food, prepared without proper monitoring, is a risk factor for deployed personnel developing diarrheal illness. Additional information is needed to better understand disease risks to personnel conducting humanitarian assistance activities in the Latin America Region.

Expression of colonization factor CS5 of enterotoxigenic Escherichia coli (ETEC) is enhanced in vivo and by the bile component Na glycocholate hydrate

Enterotoxigenic Escherichia coli (ETEC) is an important cause of acute watery diarrhoea in developing countries. Colonization factors (CFs) on the bacterial surface mediate adhesion to the small intestinal epithelium. Two of the most common CFs worldwide are coli surface antigens 5 and 6 (CS5, CS6). In this study we investigated the expression of CS5 and CS6 in vivo, and the effects of bile and sodium bicarbonate, present in the human gut, on the expression of CS5. Five CS5+CS6 ETEC isolates from adult Bangladeshi patients with acute diarrhoea were studied. The level of transcription from the CS5 operon was approximately 100-fold higher than from the CS6 operon in ETEC bacteria recovered directly from diarrhoeal stool without sub-culturing (in vivo). The glyco-conjugated primary bile salt sodium glycocholate hydrate (NaGCH) induced phenotypic expression of CS5 in a dose-dependent manner and caused a 100-fold up-regulation of CS5 mRNA levels; this is the first description of NaGCH as an enteropathogenic virulence inducer. The relative transcription levels from the CS5 and CS6 operons in the presence of bile or NaGCH in vitro were similar to those in vivo. Another bile salt, sodium deoxycholate (NaDC), previously reported to induce enteropathogenic virulence, also induced expression of CS5, whereas sodium bicarbonate did not.

Morbidity of foreign travelers in Attica, Greece: a retrospective study

Over the last decade, travel medicine was mainly focused on the epidemiology of diseases among travelers to developing countries. However, less is known about travel-related morbidity in Europe. We evaluated the demographic and clinical characteristics of foreign travelers to Greece during a 5-year period (01/01/2005 - 31/12/2009) who sought medical services from a network of physicians performing house-call visits (SOS Doctors) in the area of Attica, Greece. Overall, 3,414 foreign travelers [children (≤18 years of age): 27%] were identified; 151 (4.4%) required transfer to a hospital. The most common clinical entities were: respiratory disorders (34%), diarrheal disease (19%), musculoskeletal (12%), dermatologic (7%), non-diarrheal gastrointestinal (6%), and genitourinary (5%) disorders. Respiratory disorders were the most frequent diagnosis during all seasons, followed by diarrheal gastrointestinal and musculoskeletal disorders. Respiratory and dental conditions were observed significantly more frequently in children. Respiratory disorders were observed significantly more frequently during winter (47%) compared to spring (36.7%), summer (30.9%), and autumn (30.5%), (p < 0.01). Despite the limitations of the retrospective methodology, our findings suggest that mild, self-limited respiratory events may be the prevalent cause for seeking primary health care during travel to Greece. Our findings may be extrapolated to other countries with similar climatic and socioeconomic status.

Adaptive evolution of class 5 fimbrial genes in enterotoxigenic Escherichia coli and its functional consequences

Class 5 fimbriae of enterotoxigenic Escherichia coli (ETEC) comprise eight serologically discrete colonization factors that mediate small intestinal adhesion. Their differentiation has been attributed to the pressure imposed by host adaptive immunity. We sequenced the major pilin and minor adhesin subunit genes of a geographically diverse population of ETEC elaborating CFA/I (n = 31), CS17 (n = 20), and CS2 (n = 18) and elucidated the functional effect of microevolutionary processes. Between the fimbrial types, the pairwise nucleotide diversity for the pilin or adhesin genes ranged from 35-43%. Within each fimbrial type, there were 17 non-synonymous and 1 synonymous point mutations among all pilin or adhesin gene copies, implying that each fimbrial type was acquired by ETEC strains very recently, consistent with a recent origin of this E. coli pathotype. The 17 non-synonymous allelic differences occurred in the CFA/I pilin gene cfaB (two changes) and adhesin gene cfaE (three changes), and CS17 adhesin gene csbD (12 changes). All but one amino acid change in the adhesins clustered around the predicted ligand-binding pocket. Functionally, these changes conferred an increase in cell adhesion in a flow chamber assay. In contrast, the two mutations in the non-adhesive CfaB subunit localized to the intersubunit interface and significantly reduced fimbrial adhesion in this assay. In conclusion, naturally occurring mutations in the ETEC adhesive and non-adhesive subunits altered function, were acquired under positive selection, and are predicted to impact bacteria-host interactions.

Inconvenience due to travelers' diarrhea: a prospective follow-up study

BACKGROUND

Limited data exist documenting the degree to which travelers are inconvenienced by travelers' diarrhea (TD). We performed a prospective follow-up study at the travel clinic of Leiden University Medical Center in The Netherlands to determine the degree of inconvenience and to determine how experiencing TD affects travelers' perception.

METHODS

Healthy adults who intended to travel to the (sub)tropics for less than two months were invited to take part. Participants filled out a web-based questionnaire before departure and after returning home. TD was defined as three or more unformed stools during a 24-hour period.

RESULTS

390 of 776 Eligible travelers completed both questionnaires. Participants' median age was 31 years and mean travel duration 23 days. Of 160 travelers who contracted TD (incidence proportion 41%, median duration of TD episode 2.5 days) the majority (107/160, 67%) could conduct their activity program as planned despite having diarrhea. However, 21% (33/160) were forced to alter their program and an additional 13% (20/160) were confined to their accommodation for one or more daylight days; 53 travelers (33%) used loperamide and 14 (9%) an antibiotic. Eight travelers (5%) consulted a physician for the diarrheal illness. When asked about the degree of inconvenience brought on by the diarrheal illness, 39% categorized it as minor or none at all, 34% as moderate and 27% as large or severe. In those who regarded the episode of TD a major inconvenience, severity of symptoms was greater and use of treatment and necessity to alter the activity program were more common. Travelers who contracted travelers' diarrhea considered it less of a problem in retrospect than they had thought it would be before departure.

CONCLUSION

Conventional definitions of TD encompass many mild cases of TD (in our study at least a third of all cases) for which treatment is unlikely to provide a significant health benefit. By measuring the degree of inconvenience brought on by TD, researchers and policy makers may be able to better distinguish 'significant TD' from mild TD, thus allowing for a more precise estimation of the size of the target population for vaccination or stand-by antibiotic prescription and of the benefit of such measures.

Management of the returning traveler with diarrhea

Traveler's diarrhea (TD) strikes 20-60% of travelers visiting developing countries. It occurs shortly after the return and can be distinguished into two categories: acute and persistent TD. Acute TD, mostly caused by bacterial and viral pathogens, is usually mild and self-limited, and deserves empirical symptomatic and/or antibiotic therapy in selected cases. Fluoroquinolones are progressively superseded in this indication by azithromycin, a well tolerated macrolide active against most bacteria responsible for TD, including the quinolone-resistant species of Campylobacter jejuni that are now pervasive, especially in Southeast Asia and India. Persistent TD in the returning traveler is much rarer than its acute counterpart and may be associated with three types of causes. Persistent infections, among which Giardia and possibly Entamoeba predominate, account for a significant proportion of cases. Postinfectious processes represent a second cause and comprise temporary lactose malabsorption and postinfectious irritable bowel syndrome, now considered a major cause of persistent TD. Finally, apparently unrelated chronic diseases causing diarrhea are occasionally unmasked by TD and represent a third type of persistent TD, among which the well established case of incident inflammatory bowel disease poses intriguing pathogenesis questions. This review discusses recent advances in the field and provides practical recommendations for the management of TD in adult, immunocompetent returning travelers.

Clinical characteristics and etiology of travelers' diarrhea among Korean travelers visiting South-East Asia

The morbidity of travelers' diarrhea (TD) is still high. This study examined the incidence of common pathogens and characteristics of TD among Korean travelers who visited South-East Asian countries. We performed a prospective study involving 479 Korean travelers with diarrheal disease from February 2009 to April 2009 and stool samples were examined and questionnaire surveys were done after arrival. Enterotoxigenic Escherichia coli (ETEC) was found in 36.0% of TD cases, as were the following: Enteroaggregative Escherichia coli (EAEC) in 27.0%, Vibrio parahaemolyticus in 13.1%, and Norovirus in 11.5%. The detected rate of classic TD was higher in men (P = 0.007), in patients who had a shorter duration trip (P = 0.023) and in patients who drank more than 1 liter of water per day (P = 0.037). Positive stool culture rates were higher in men (P = 0.005), in hospitalized patients (P = 0.013). and in those who consumed impure water or raw foods (P = 0.033). A higher severity of disease corresponded to a significantly higher culture positivity rate (P = 0.029). We should consider the possibility of other pathogens in addition to ETEC in patients with TD who visit South-East Asia. Travelers need to educate about risk factors associated with TD.

Diarrhoea in a large prospective cohort of European travellers to resource-limited destinations

BACKGROUND

Incidence rates of travellers' diarrhoea (TD) need to be updated and risk factors are insufficiently known.

METHODS

Between July 2006 and January 2008 adult customers of our Centre for Travel Health travelling to a resource-limited country for the duration of 1 to 8 weeks were invited to participate in a prospective cohort study. They received one questionnaire pre-travel and a second one immediately post-travel. First two-week incidence rates were calculated for TD episodes and a risk assessment was made including demographic and travel-related variables, medical history and behavioural factors.

RESULTS

Among the 3100 persons recruited, 2800 could be investigated, resulting in a participation rate of 89.2%. The first two-weeks incidence for classic TD was 26.2% (95%CI 24.5-27.8). The highest rates were found for Central Africa (29.6%, 95% CI 12.4-46.8), the Indian subcontinent (26.3%, 95%CI 2.3-30.2) and West Africa (21.5%, 95%CI 14.9-28.1). Median TD duration was 2 days (range 1-90). The majority treated TD with loperamide (57.6%), while a small proportion used probiotics (23.0%) and antibiotics (6.8%). Multiple logistic regression analysis on any TD to determine risk factors showed that a resolved diarrhoeal episode experienced in the 4 months pre-travel (OR 2.03, 95%CI 1.59-2.54), antidepressive comedication (OR 2.11, 95%CI 1.17-3.80), allergic asthma (OR 1.67, 95%CI 1.10-2.54), and reporting TD-independent fever (OR 6.56, 95%CI 3.06-14.04) were the most prominent risk factors of TD.

CONCLUSIONS

TD remains a frequent travel disease, but there is a decreasing trend in the incidence rate. Patients with a history of allergic asthma, pre-travel diarrhoea, or of TD-independent fever were more likely to develop TD while abroad.

Ancestral lineages of human enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) is a common cause of diarrhea among children living in and among travelers visiting developing countries. Human ETEC strains represent an epidemiologically and phenotypically diverse group of pathogens, and there is a need to identify natural groupings of these organisms that may help to explain this diversity. Here, we sought to identify most of the important human ETEC lineages that exist in the E. coli population, because strains that originate from the same lineage may also have inherited many of the same epidemiological and phenotypic traits. We performed multilocus sequence typing (MLST) on 1,019 ETEC isolates obtained from humans in different countries and analyzed the data against a backdrop of MLST data from 1,250 non-ETEC E. coli and eight ETEC isolates from pigs. A total of 42 different lineages were identified, 15 of which, representing 792 (78%) of the strains, were estimated to have emerged >900 years ago. Twenty of the lineages were represented in more than one country. There was evidence of extensive exchange of enterotoxin and colonization factor genes between different lineages. Human and porcine ETEC have probably emerged from the same ancestral ETEC lineage on at least three occasions. Our findings suggest that most ETEC strains circulating in the human population today originate from well-established, globally widespread ETEC lineages. Some of the more important lineages identified here may represent a smaller and more manageable target for the ongoing efforts to develop effective ETEC vaccines.

Noroviruses as a cause of diarrhea in travelers to Guatemala, India, and Mexico

Noroviruses (NoVs) are increasingly being recognized as an important enteric pathogen of gastroenteritis worldwide. The prevalence of NoVs as a cause of diarrhea acquired by travelers in developing countries is not well known. We examined the prevalence and importance of NoV infection in three international traveler cohorts with diarrhea acquired in three developing regions of the world, Mexico, Guatemala, and India. We also characterized the demographics and symptoms associated with NoV diarrhea in these travelers. Stool samples from 571 international travelers with diarrhea were evaluated for traditional enteropathogens. NoVs were identified using reverse transcription-PCR and probe hybridization. NoVs were identified in 10.2% of cases of travelers' diarrhea and, overall, was the second most common pathogen, following diarrheagenic Escherichia coli. The detection of NoV diarrhea significantly varied over the three study time periods in Guadalajara, Mexico, ranging from 3 of 98 (3.0%) diarrheal stools to 12 of 100 (12.0%) fecal specimens (P=0.03). The frequency of NoV diarrhea was also dependent upon the geographic region, with 17 of 100 (17.0%) travelers to Guatemala, 23 of 194 (11.9%) travelers to India, and 3 of 79 (3.8%) travelers to Mexico testing positive for NoVs from 2002 to 2003 (P=0.02). NoVs are important pathogens of travelers' diarrhea in multiple regions of the world. Significant variation in the prevalence of NoV diarrhea and in the predominant genogroup infecting travelers was demonstrated, dependent upon the specific geographic location and over time.

Descriptive epidemiology of travel-associated diarrhea based on surveillance data at Narita International Airport

BACKGROUND

Although travelers' diarrhea is one of the most common health problems among international travelers, current findings depend largely on hospital and clinic-based information. To better understand the disease epidemiology and to identify specific subpopulations with increased risks, denominator data covering a large traveler population are needed.

METHODS

We conducted a questionnaire survey of all travelers at the quarantine station, Narita International Airport, and retrospectively reviewed records from January 2001 to December 2005. The Immigration Bureau database was used as denominator data on travel patterns during the same period. To elucidate the risks of contracting diarrhea, we estimated incidence according to age, sex, month of travel, and travel destination.

RESULTS

A total of 7,937,654 people voluntarily submitted questionnaires; 9,836 had travelers' diarrhea. Travelers of both sexes aged 20 to 29 years reported the disease most frequently. Men aged 20 to 24 had the highest estimated incidence compared with any other age and sex group. The incidence was higher in March, August, and September than other months, mainly due to the influx of young adult travelers. Travel to south-central Asia, Southeast Asia, and North Africa was associated with higher risks than that to other areas.

CONCLUSIONS

Risks of contracting travelers' diarrhea are dependent on age, sex, season, and destination of travel. Incidence of diarrhea in all four seasons varies with age. Some destinations are associated with increased risks regardless of age. To prevent travelers from contracting diarrhea, adequate measures should focus on specific subpopulations.

Defining infections in international travellers through the GeoSentinel surveillance network

International travellers are often exposed to a wide range of infections, most of which are a reflection of common diseases in the destination country. The consequences of acquiring such infections are serious and can be associated with substantial morbidity and mortality. Attempting to define the range of infections and the risk factors that are associated with acquiring them during travel to different regions worldwide will provide an evidence base for the development and implementation of effective preventative interventions. This Science and Society article focuses on the valuable function served by the GeoSentinel surveillance network in defining the range of infections in travellers.

Overseas outbreaks of infectious intestinal disease identified in Scotland, 2003 to 2007

BACKGROUND

This article presents information on all potential outbreaks of infectious intestinal disease (IID) identified by Health Protection Scotland (HPS) involving residents of Scotland. Unlike other systems, this alert system covers potential outbreaks of IID rather than apparently sporadic cases and covers all gastrointestinal pathogens, all visited countries, and all groups of travelers.

METHODS

HPS collects information on all potential outbreaks of IID in residents of Scotland where infection is believed to have been acquired abroad and disseminates this to all public health teams in Scotland so other linked cases can be identified. Where possible HPS also disseminates the details to the national surveillance center in the country where infection is believed to have been acquired, enabling them to facilitate any investigations or control measures they believe necessary. The rate of outbreaks associated with travel to particular countries was determined using the number of visits reported for residents of Scotland from Travel Trends data from the Office of National Statistics.

RESULTS

Between 2003 and 2007, 319 such potential outbreaks were identified. Spain was the most frequently identified country reflecting the fact that it was also the most frequently visited country; the rate per 100,000 visits to Spain was 1.4, very similar to the overall rate for all countries of 1.3, while the highest rate of 46.7 per 100,000 visitors was associated with travel to Egypt. Salmonella sp was the most frequently identified pathogen within which Salmonella enteritidis was the most frequently identified serotype.

CONCLUSIONS

The system provides a rapid alert mechanism for potential outbreaks of IID outside Scotland, allowing their investigation and control as appropriate and demonstrates the risks of outbreaks associated with different countries and pathogens.