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

Emergency Care for High-Altitude Trekking and Climbing

Introduction: High altitude regions are characterized by harsh conditions (environmental, rough terrain, natural hazards, and limited hygiene and health care), which all may contribute to the risk of accidents/emergencies when trekking or climbing. Exposure to hypoxia, cold, wind, and solar radiation are typical features of the high altitude environment. Emergencies in these remote areas place high demands on the diagnostic and treatment skills of doctors and first-aiders. The aim of this review is to give insights on providing the best possible care for victims of emergencies at high altitude. Methods: Authors provide clinical recommendations based on their real-world experience, complemented by appropriate recent studies and internationally reputable guidelines. Results and Discussion: This review covers most of the emergencies/health issues that can occur when trekking or during high altitude climbing, that is, high altitude illnesses and hypothermia, freezing cold injuries, accidents, for example, with severe injuries due to falling, cardiovascular and respiratory illnesses, abdominal, musculoskeletal, eye, dental, and skin issues. We give a summary of current recommendations for emergency care and pain relief in case of these various incidents.

Diarrhea and related personal characteristics among Japanese university students studying abroad in intermediate- and low-risk countries

Despite an increasing number of students studying abroad worldwide, evidence about health risks while they are abroad is limited. Diarrhea is considered the most common travelers' illness, which would also apply to students studying abroad. We examined diarrhea and related personal characteristics among Japanese students studying abroad. Japanese university students who participated in short-term study abroad programs between summer 2016 and spring 2018 were targeted (n = 825, 6-38 travel days). Based on a 2-week-risk of diarrhea (passing three or more loose or liquid stools per day) among travelers by country, the destination was separated into intermediate- and low-risk countries. After this stratification, the associations between personal characteristics and diarrhea during the first two weeks of their stay were evaluated using logistic regression models. Among participants in intermediate-risk countries, teenagers, males and those with overseas travel experience were associated with an elevated risk of diarrhea; the odds ratios (95% confidence intervals) were 2.42 (1.08-5.43) for teenagers (vs. twenties), 1.93 (1.08-3.45) for males (vs. females) and 2.37 (1.29-4.33) for those with overseas experience (vs. none). Even restricting an outcome to diarrhea during the first week did not change the results substantially. The same tendency was not observed for those in the low-risk countries. Teenage students, males and those with overseas travel experience should be cautious about diarrhea while studying abroad, specifically in intermediate-risk countries.

A Two-Week Vacation in the Tropics and Psychological Well-Being-An Observational Follow-Up Study

Despite the vast annual number of international visitors to the tropics, surprisingly little data are available on the psychological well-being associated with the travels or with travelers’ diarrhoea (TD). We herein recruited participants of a vaccination trial, OEV-123, before their 12-day holiday in Benin, West Africa. We assessed the travelers’ psychological distress with a general health questionnaire (GHQ-12) and retrieved data on TD from the trial database. The GHQ-12 was completed before (wave 0), at return (wave 1), and 1-month after (wave 2) the trip. Of the 174 participants, 73% were women, with a mean age 40 years. Moreover, 24% reported psychological distress before traveling, 10% immediately after, and 16% 1-month after the trip (GHQ-12, 3 or more; 0−12 scoring). The findings showed that psychological well-being increased after the tropical holiday. The GHQ-12 middle wave sum score differed from the wave 0 (p < 0.001) and wave 2 (p = 0.008) sum scores, with travelers reporting highest levels of well-being on their return, with evidence of a lasting improvement. TD was experienced by 71%, and it had a negative impact on psychological well-being only if experienced after travel.

Travellers' diarrhoea - prevention, trends and role of microbiome

OBJECTIVES

In this review, we present a contemporary look at the management of travellers' diarrhoea (TD), and we discuss the potential role of a microbiome as well as the administration of live microorganisms in order to prevent TD.

METHODS

We performed a comprehensive search using the PubMed and Web of Science databases for the period 2014-2021, looking for original and review articles on travellers' diarrhoea.

RESULTS

TD belongs among the most frequent illnesses experienced by travellers. For the most part, it is manifested as an acute yet self limiting condition, and only in a few cases proceeds to a prolonged form. Epidemiological analyses have shown that the majority of TD cases are caused by bacterial infections. In practice, pharmacological therapy is often used in the prevention and treatment of TD, since patients naturally seek preventive measures against the development of its severe course and its impact on planned activities. Bismuth salicylate is a strongly recommended TD prophylaxis but is not available on all European Union markets. Although the antibiotic prophylaxis is not generally recommended in guidelines, some antibiotic or chemotherapeutic agents are accessible over-the-counter in certain countries, and travellers are routinely encouraged to use them preventively. This routine can alter the microbiome of the traveller and promote the spread of drug resistant bacteria in their place of residence. Probiotic administration is considered safe, although the quality of evidence in favour of its prophylactic use in TD is currently low.

CONCLUSIONS

The challenge for public health authorities is to educate personnel that can directly influence the behaviour of travellers through safe and effective pharmacological alternatives to antibiotics. Manipulation of the gut microbiome using specific probiotic strains can represent a safe and promising intervention.

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.

Extended-spectrum beta-lactamase-producing strains among diarrhoeagenic Escherichia coli-prospective traveller study with literature review

BACKGROUND

Antibiotics are no longer the primary approach for treating all travellers' diarrhoea (TD): most cases resolve without antibiotics and using them predisposes to colonization by multidrug-resistant bacteria. Data are accumulating on increasing resistance among TD pathogens, yet research into the most common agents, diarrhoeagenic Escherichia coli (DEC), remains limited.

METHODS

A total of 413 travellers to the (sub)tropics were analyzed for travel-acquired diarrhoeal pathogens and ESBL-PE. To identify ESBL-producing DEC, ESBL-producing E. coli (ESBL-EC) isolates were subjected to multiplex qPCR for various DEC pathotypes: enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC) and enterohaemorrhagic (EHEC) E. coli.For a literature review, we screened studies among travellers and locals in low- and middle-income countries (LMICs) on the frequency of ESBL-producing DEC, and among travellers, also DEC with resistance to ciprofloxacin, azithromycin, and rifamycin derivatives.

RESULTS

Our rate of ESBL-EC among all DEC findings was 2.7% (13/475); among EAEC 5.7% (10/175), EPEC 1.1% (2/180), ETEC 1.3% (1/80) and EHEC (0/35) or EIEC 0% (0/5). The literature search yielded three studies reporting ESBL-EC frequency and thirteen exploring resistance to TD antibiotics among travel-acquired DEC. For EAEC and ETEC, the ESBL-EC rates were 10-13% and 14-15%, resistance to fluoroquinolones 0-42% and 0-40%, azithromycin 0-29% and 0-61%, and rifaximin 0% and 0-20%. The highest rates were from the most recent collections. Proportions of ESBL-producing DEC also appear to be increasing among locals in LMICs and even carbapenemase-producing DEC were reported.

CONCLUSION

ESBL producers are no longer rare among DEC, and the overall resistance to various antibiotics is increasing. The data predict decreasing efficacy of antibiotic treatment, threatening its benefits, for disadvantages still prevail when efficacy is lost.

A prospective observational study describing severity of acquired diarrhea among U.S. military and Western travelers participating in the Global Travelers' Diarrhea Study

BACKGROUND

Travelers' diarrhea (TD) is one of the most common illnesses affecting modern-day travelers, including military personnel. Previous work has shown that afflicted travelers may alter their itineraries and be confined to bed rest due to symptoms, and military personnel may become incapable of completing operational requirements. Examination of signs, symptoms, and severity of diarrheagenic pathogens can inform clinical diagnosis and prioritization of future surveillance and research activities.

METHODS

Utilizing a global laboratory network, culture and molecular testing were performed in parallel at each site on a group of core pathogens, and definitions for acute diarrhea (AD), severe AD, acute gastroenteritis (AGE), and severe AGE were determined using data elements in the modified Vesikari scale. We included 210 cases of TD reporting all variables of interest in our severity assessment analysis.

RESULTS

Out of all cases, 156/210 (74%) met criteria for severe AD and 35/210 (17%) for severe AGE. Examination of severity by pathogen revealed that, at non-military sites, 17/19 (89%) of enteropathogenic Escherichia coli (E. coli) (EPEC) infections, 28/32 (88%) of enterotoxigenic E. coli (ETEC) infections, and 13/15 (87%) of Shigella/enteroinvasive E. coli (EIEC) infections resulted in severe AD cases. At the military site, all infections of ETEC (6/6), Shigella-EIEC (4/4), and enteroaggregative E. coli (EAEC) resulted in AD. Norovirus infections at non-military and military sites resulted in 27% (14/51) and 33% (3/9) severe AGE cases, respectively.

CONCLUSIONS

This study found a high percentage of participants enrolled at both military and non-military sites experienced severe AD with concerning numbers of severe cases at non-military sites reporting hospitalization and reductions in performance. Since travelers with mild TD symptoms are less likely to present to health care workers than those with more severe TD, there is a potential selection bias in this study that may have overestimated the proportion of more severe outcomes among all individuals who could have participated in the GTD study. Future research should examine other covariates among pathogen and host, such as treatment and comorbid conditions, that may contribute to the presence of signs and symptoms and their severity.

Predictors of aetiology and outcomes of acute gastrointestinal illness in returning travellers: a retrospective cohort analysis

BACKGROUND

Gastrointestinal illness is a major cause of morbidity in travellers and is a common reason for presentation to healthcare services on return. Whilst the aetiology of imported gastrointestinal disease is predominantly infectious, outcomes are variable due to a range of phenomena such as post-infectious irritable bowel syndrome, drug resistance and occult pathology (both infectious and non-infectious). Previous studies have focussed on predictors of aetiology of gastrointestinal disease in travellers; we present a retrospective study combining both aetiological and early outcome data in a large cohort of returned travellers.

METHOD

We identified 1450 patients who attended our post-travel walk-in clinic with gastrointestinal symptoms between 2010 and 2016. Demographic, travel, clinical and laboratory data was collected through case note review. Logistic regression analysis to examine correlates of aetiology and outcome were performed in R (CRAN Project 2017).

RESULTS

Of 1450 patients in our cohort 153 reported bloody diarrhoea and 1081 (74.6%) reported non-bloody diarrhoea. A definitive microbiological diagnosis was made in 310 (20.8%) of which 137 (9.4%) had a parasite identified and 111 (7.7%) had a bacterial cause identified. Factors associated with a parasitological diagnosis included history of travel to South Asia (aOR = 2.55; 95%CI 1.75-3.70, p < 0.0001) and absence of bloody diarrhoea (aOR = 0.22; 95%CI 0.066-0.53, p < 0.005). Factors associated with a bacteriological diagnosis included male gender (aOR = 1.69; 95%CI 1.10-2.62, p < 0.05), an age < 37 years on presentation (aOR = 2.04; 95%CI 1.25-3.43, p < 0.01), white cells on stool microscopy (aOR = 3.52; 95%CI 2.09-5.86, p < 0.0001) and a C-reactive protein level of >5iu/dL (aOR = 4.68; 95%CI 2.91-7.72, p < 0.0001). The majority (1235/1450, 82.6%) reported full symptomatic resolution by the first follow up visit; factors associated with lack of symptomatic resolution included female gender (aOR = 1.45 95%CI 1.06-1.99, p < 0.05), dysenteric diarrhoea (aOR = 2.14 (95%CI 1.38-3.25, p < 0.0005) and elevated peripheral leukocyte count (aOR = 1.58 95%CI 1.02-2.40, p < 0.05).

CONCLUSIONS

In a cohort of returned travellers, we were able to identify multiple factors that are correlated with both aetiology and outcome of imported gastrointestinal syndromes. We predict these data will be valuable in the development of diagnostic and therapeutic pathways for patients with imported gastrointestinal infections.

Revisiting travellers' diarrhoea justifying antibiotic treatment: prospective study

BACKGROUND

As antimicrobials increase the risk of acquiring multidrug-resistant (MDR) bacteria, unnecessary antibiotics should be avoided for travellers' diarrhoea (TD). Antibiotics are recommended in TD accompanied by fever or incapacitation (TD justifying use of antibiotics, TDjuAB). Seeking tools for reducing antibiotic use, we explored factors predisposing to TDjuAB and scrutinized antibiotic treatment among those with TDjuAB [TDjuAB(+) subgroup] and those with diarrhoea not justifying antibiotics [TDjuAB(-) subgroup].

METHODS

We conducted a study among 370 prospectively recruited visitors to the tropics. Stool samples and questionnaires were collected before and after travel. Enteric pathogens were analysed by qPCR for enteropathogenic (EPEC), enteroaggregative (EAEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC) and enteroinvasive (EIEC) E. coli/Shigella, Campylobacter, Salmonella, Yersinia and Vibrio cholerae, and for ETEC's toxins LT (heat-labile), STh (human heat-stable) and STp (porcine heat-stable). TD was defined by the WHO criteria and TDjuAB as diarrhoea accompanied by fever, and/or disrupting or preventing daily activities. Multivariable analysis was applied-separately for travel-related factors and pathogens-to identify risk factors for TDjuAB(+).

RESULTS

Among the 370 travellers, TD was contracted by 253 (68%), categorized as TDjuAB(+) in 93/253 (37%) and TDjuAB(-) in 160/253 (63%) of the cases. Antibiotics were used for TD by 41% in TDjuAB(+) and by 7% in the TDjuAB(-) group. Relative risk ratios (RRR)s are presented for both the TDjuAB(+) and the TDjuAB(-) groups. TDjuAB(+) was associated with long travel duration and young age. Among the 298 subjects not having taken antibiotics, increased RRRs were found e.g. for findings of Campylobacter coli/jejuni and ETEC's STh toxin.

CONCLUSIONS

The first to analyse risk factors for TDjuAB, our study presents RRRs for demographic and behavioural factors and for various pathogens. Only less than half of those in the TDjuAB(+) group took antibiotics, which demonstrates that most cases meeting the current criteria recover without antimicrobial treatment.

Bacterial, viral and parasitic pathogens analysed by qPCR: Findings from a prospective study of travellers' diarrhoea

BACKGROUND

The diagnostics of travellers' diarrhoea (TD) has been revolutionised by multiplex qPCR assays. While mostly of bacterial aetiology, viruses and parasites account for the disease among 10-20% of travellers. Despite this, prospective studies applying qPCR assays remain scarce that cover not only bacteria, such as the various diarrhoeagenic Escherichia coli (DEC), but also viral and parasitic pathogens.

METHOD

We analysed by qPCR pre- and post-travel stool samples of 146 Finnish travellers for bacterial, viral and parasitic pathogens: enteropathogenic (EPEC), enteroaggregative (EAEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC), and enteroinvasive (EIEC) E. coli; Shigella, Campylobacter, Salmonella, Yersinia and Vibrio cholerae; norovirus G1 and G2, rotavirus, enteroviruses, and sapovirus; and Giardia lamblia, Entamoeba histolytica, and Cryptosporidium. Symptoms and medication data during travel were collected by questionnaires.

RESULTS

We detected bacterial pathogens in 102/146 samples (69.9%; EAEC, EPEC, ETEC most common), viral ones in 13 (8.9%; norovirus most common), and parasitic ones in one (0.7%; Giardia). Noroviruses were associated with severe symptoms (23.5% versus non-severe 4.9%). In the TD group, 41.7% (5/12) of those with viral pathogens (vs. 13.3%; 11/83 without) took antibiotics.

CONCLUSION

Viral pathogens, particularly noroviruses, prevail in severe TD. The symptoms of viral disease are often severe and lead to unwarranted use of antibiotics.

Use of face masks and other personal preventive measures by Hajj pilgrims and their impact on health problems during the Hajj

BACKGROUND

The Hajj is one of the world's largest pilgrimage and gathers millions of Muslims from different nationalities every year. Communicable diseases have been reported frequently, during and following the Hajj, and these have been linked to individual behavioural measures. This study aimed to measure the effect of personal preventive measures, such as face mask use, hand hygiene and others, adopted by pilgrims in reducing the acquisition of infectious diseases.

METHODS

We conducted a cross-sectional study at the Hajj terminal in King Abdulaziz International Airport in Jeddah, Saudi Arabia. Pilgrims were approached in the airport lounges after the 2017 Hajj season and prior to the departure of their flights from Jeddah to their home countries. An electronic data collection tool ('Open Data Kit') was used to gather survey data in regards to health problems and preventive measures during the Hajj.

RESULTS

A total of 2973 Hajj pilgrims were surveyed. In all, 38.7% reported symptoms of upper respiratory tract infections (URTIs) and 5.4% reported symptoms of travel diarrhoea. Compliance with face mask use was 50.2%. Changing a face mask every 4 h was found to be significantly associated with lower prevalence of URTIs [adjusted odds ratio 0.56 (95% confidence interval 0.34-0.92), P = 0.02]. There was no statistical difference between overall face mask use and URTI acquisition. The main sources of food, eating raw vegetables/food, frequency of hand washing or use of hand sanitizers were not found to be significantly associated with reported travellers' diarrhoea. Unlicensed barbers were used by 12% of pilgrims and 9.2% of pilgrims reported using blades that were reused by other pilgrims.

CONCLUSION

Preventive measures are the most effective way to prevent infections. Pilgrims can benefit from face masks by changing them frequently. There is still limited information on the effect of the use of face mask in decreasing the risk of URTI in mass gatherings.

Prescribing Patterns of Antibiotics for the Self-Treatment of Travelers' Diarrhea in Global TravEpiNet, 2009-2018

Background

International travelers are often prescribed antibiotics for self-treatment of travelers' diarrhea (TD), but the benefits and risks of antibiotics are debated. We assessed the prescribing patterns of empiric antibiotics for TD in international travelers evaluated at Global TravEpiNet (GTEN) sites (2009-2018).

Methods

We performed a prospective, multisite cross-sectional study regarding antibiotic prescriptions for the self-treatment of TD at 31 GTEN sites providing pretravel consultations to adult international travelers. We described traveler demographics, itineraries, and antibiotic(s) prescribed. We used multivariable logistic regressions to assess the association of year of consultation with antibiotic prescribing (yes/no) and class (fluoroquinolones vs azithromycin). We performed interrupted time-series analyses to examine differences in prescribing before and after the Food and Drug Administration (FDA) warning on fluoroquinolones (July 2016).

Results

Antibiotics were not prescribed in 23 096 (22.2%) of 103 843 eligible pretravel GTEN consultations; azithromycin and fluoroquinolones were most frequently prescribed. Antibiotic prescribing declined significantly each year between 2009 and 2018 (odds ratio [OR], 0.84; 95% CI, 0.79-0.89), as did fluoroquinolone prescribing, relative to azithromycin (OR, 0.77; 95% CI, 0.73-0.82). The rate of decline in fluoroquinolone prescribing was significantly greater after the FDA fluoroquinolone warning (15.3%/year) than before (1.1%/year; P < .001).

Conclusions

Empiric antibiotics for TD were prescribed in >75% of pretravel GTEN consultations, but antibiotic prescribing declined steadily between 2009 and 2018. Fluoroquinolones were less frequently prescribed than azithromycin, especially after the 2016 FDA fluoroquinolone warning. Emphasis on the risks of antibiotics may influence antibiotic prescribing by providers for empiric treatment of TD.

Incidence of Travelers' Diarrhea among Adult Foreign Travelers in Thailand: A Prospective Study

Travelers' diarrhea (TD) is common among foreign travelers to Thailand. We performed a prospective cohort study to determine the TD incidence among foreign adult travelers to Thailand. We retrieved baseline demographic data, travel plans, and health history on enrolling individuals and collected follow-up questionnaires on days 7, 14, and 28 from the day of arrival. We analyzed data from 349 eligible participants. The mean participants' age was 32.3 years; 55.4% were men. Most of the participants had visited a travel clinic for vaccinations and counseling after arrival in Thailand. The cumulative incidences of the participants developing TD were 14.0% (49/349), 23.5% (82/349), and 33.0% (115/349) at 7, 14, and 28 days, respectively. The median time to develop TD was 9 days (interquartile range 5-18 days) post-arrival. Of 115 participants with TD, 64.3% (74/115) consulted a physician, 1.7% (2/115) were hospitalized, and 11.3% (13/115) had to change their travel plans. We identified young age, eating street food, and not routinely washing hands after using a toilet as risk factors significantly associated with the incidence of TD using the log-rank test in our survival analysis. Up to one-third of foreign travelers developed diarrhea during the first month, and some cases were severe. Although no highly effective TD prevention method exists, the practice of good personal hygiene and avoidance of food and drinks derived from unsanitary sources are still recommended to reduce the risk of travelers' TD.

Travelers' diarrhea: update on the incidence, etiology and risk in military and similar populations - 1990-2005 versus 2005-2015, does a decade make a difference?

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Estimating the incidence of norovirus acute gastroenteritis among US and European international travelers to areas of moderate to high risk of traveler's diarrhea: a prospective cohort study protocol

Background

Acute gastroenteritis (AGE) is the leading cause of illness among returning travelers seeking medical care. Multiple types of enteric pathogens can cause travel-acquired AGE and, while bacterial pathogens have a predominant role, the importance of viruses, such as norovirus, is increasingly recognized. There is a lack of information on travel-acquired norovirus incidence among symptomatic and asymptomatic individuals irrespective of healthcare-seeking behavior. Our aim is to estimate the incidence of travel-acquired AGE due to norovirus and to characterize the burden of disease among international travelers from the United States and Europe.

Methods

We describe a prospective cohort study implemented in five US and European sites to estimate the role of AGE due to norovirus among adult international travelers. We enrolled individuals aged 18 years and older who are traveling to regions of moderate-high risk of AGE, or via cruise ship with an international port stop, with a trip duration of 3–15 days. The study will generate a wide range of health and travel-related data for pre-, during, and up to 6-months post-travel. We will identify laboratory-confirmed travel-acquired norovirus infections among both symptomatic and asymptomatic individuals from self-collected whole stool samples tested via quantitative RT-PCR. Coinfections will be identified in a subset of travelers with AGE using a multiplex molecular-based assay.

Discussion

This study is unique in design and breadth of data collected. The prospective collection of health and behavioral data, as well as biologic samples from travelers irrespective of symptoms, will provide useful data to better understand the importance of norovirus AGE among international travelers. This study will provide data to estimate the incidence of norovirus infections and AGE and the risk of post-infectious sequelae in the 6-month post-travel period serving as a baseline for future norovirus AGE vaccination studies. This study will contribute valuable information to better understand the role of norovirus in travel-acquired AGE risk and the impact of these infections on a broad set of outcomes.

Stand-by antibiotics encourage unwarranted use of antibiotics for travelers' diarrhea: A prospective study

BACKGROUND

As antibiotics predispose travelers to acquiring multidrug-resistant intestinal bacteria, they should no longer be considered a mainstay for treating travelers' diarrhea. It has been claimed that stand-by antibiotics are justified as a means to avoid visits to local healthcare providers which often lead to polypharmacy.

METHOD

We revisited the traveler data of 316 prospectively recruited volunteers with travelers' diarrhea by retrieving from questionnaires and health diaries information on antibiotic use, stand-by antibiotic carriage, and visits with local healthcare. Multivariable analysis was applied to identify factors associated with antibiotic use.

RESULTS

Among our 316 volunteers with travelers' diarrhea, however, carrying stand-by antibiotics seemed not to reduce the rate of healthcare-seeking; on the contrary, antibiotic use was more frequent among stand-by antibiotic carriers (34%) than non-carriers (11%). Antibiotics were equally taken for severe and incapacitating travelers' diarrhea, but compared to non-carriers, stand-by antibiotic carriers resorted to medication also for mild/moderate (38% vs. 4%) and non-incapacitating disease (29% vs. 5%). Antibiotic use was associated with stand-by antibiotic carriage (OR 7.2; 95%CI 2.8-18.8), vomiting (OR 3.5; 95%CI 1.3-9.5), incapacitating diarrhea (OR 3.6; 95%CI 1.3-9.8), age (OR 1.03; 95%CI 1.00-1.05), and healthcare visit for diarrhea (OR 465.3; 95%CI 22.5-9633.6).

CONCLUSIONS

Carriage of stand-by antibiotics encouraged less cautious use of antibiotics. Recommendations involving prescription of antibiotics for all travelers require urgent revision.

Despite antibiotic treatment of travellers' diarrhoea, pathogens are found in stools from half of travellers at return

BACKGROUND

Among visitors to the (sub)tropics, 20-50% contract travellers' diarrhoea (TD) and 5-30% take antibiotics. While shortening the duration of illness, antimicrobials predispose to acquisition of multi-drug resistant bacteria. Therefore, liberal use is no longer advocated. Although antibiotics kill pathogens, no data support the view that they could prevent post-infectious sequelae. We investigated how antibiotic use for TD abroad impacts the pathogen findings at return.

MATERIALS AND METHODS

We revisited 456 travellers' clinical data and stool pathogens examined by qPCR for Salmonella, Yersinia, Campylobacter, Shigella, Vibrio cholerae and enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC) and enteroinvasive (EIEC) Escherichia coli.

RESULTS

Among travellers with TD, antibiotic users had pathogen-positive samples less frequently than non-users (50% versus 83%). The difference was significant for EPEC (23% versus 47%) and EAEC (27% versus 54%), but not ETEC (17% versus 26%) or the other pathogens. Shigella/EIEC was found more often among antibiotic users than non-users (4% versus 1%).

CONCLUSION

Despite antibiotic treatment of TD, half of the users still had stool pathogens at return, reflecting either antibiotic resistance of pathogens or recolonisation/reinfection while abroad. Treatment of TD with antibiotics during travel should not be interpreted to indicate eradication of pathogens.

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.

Previous exposure in a high-risk area for travellers' diarrhoea within the past year is associated with a significant protective effect for travellers' diarrhoea: a prospective observational cohort study in travellers to South Asia

BACKGROUND

Travellers' diarrhoea is the most common health problem in travellers. Depending on the region visited, up to 40% of travellers develop diarrhoea during a 2-week trip. The aim of this study was to assess risk factors for TD among travellers to the Indian subcontinent.

METHODS

An observational prospective multicentre cohort study investigated travellers to the Indian subcontinent. Participants completed questionnaires assessing the incidence of travellers' diarrhoea and identifying potential risk factors. Covariates were assessed univariately, followed by a multivariate regression.

RESULTS

Two-hundred and twenty-six travellers were enrolled into the study, 178 filled in both pre- and post-travel questionnaires. Overall, the attack rate of travellers' diarrhoea was 38.2%. Travel destination is a key risk factor for the occurrence of TD. Travelling to India or Nepal vs Bhutan is associated with an increased risk for TD (OR 6.68 and 6.62, respectively). A length of stay of more than 3 weeks compared to less than 2 weeks is also associated with a significantly increased risk (OR 5.45). Having stayed in a high-risk area for travellers' diarrhoea within the past year before the current trip is associated with a significantly decreased risk (OR 0.19). No association was found between consumption of high risk food (i.e. tap water, ice cream, raw meat and hamburgers) and travellers' diarrhoea.

CONCLUSION

Travellers' diarrhoea is a frequent problem in travellers to the Indian subcontinent. Previous exposure in a high-risk area for travellers' diarrhoea within the past year appears to have a significant protective effect. Furthermore, an association between the occurrence of travellers' diarrhoea and travel destination and length of stay, respectively, was observed. Consumption of risk food did not confer a TD risk in our study.

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.

Is it worth adding loperamide to antibiotic treatment of traveler’s diarrhea?

Travelers' diarrhea is a frequent condition, especially in those traveling to high-risk areas. Although antibiotic treatment reduces the duration of diarrhea, it has been suggested adding loperamide could further reduce the symptoms. To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We identified two systematic reviews including 28 studies overall, of which 15 were randomized trials relevant for the question of interest. We extracted data from the systematic reviews, reanalysed data of primary studies and generated a summary of findings table using the GRADE approach. We concluded adding loperamide to antibiotic treatment might accelerate resolution of symptoms in traveler’s diarrhea with minimal or no adverse effects.

Guidelines for the prevention and treatment of travelers' diarrhea: a graded expert panel report

BACKGROUND

: Travelers' diarrhea causes significant morbidity including some sequelae, lost travel time and opportunity cost to both travelers and countries receiving travelers. Effective prevention and treatment are needed to reduce these negative impacts.

METHODS

: This critical appraisal of the literature and expert consensus guideline development effort asked several key questions related to antibiotic and non-antibiotic prophylaxis and treatment, utility of available diagnostics, impact of multi-drug resistant (MDR) colonization associated with travel and travelers' diarrhea, and how our understanding of the gastrointestinal microbiome should influence current practice and future research. Studies related to these key clinical areas were assessed for relevance and quality. Based on this critical appraisal, guidelines were developed and voted on using current standards for clinical guideline development methodology.

RESULTS

: New definitions for severity of travelers' diarrhea were developed. A total of 20 graded recommendations on the topics of prophylaxis, diagnosis, therapy and follow-up were developed. In addition, three non-graded consensus-based statements were adopted.

CONCLUSIONS

: Prevention and treatment of travelers' diarrhea requires action at the provider, traveler and research community levels. Strong evidence supports the effectiveness of antimicrobial therapy in most cases of moderate to severe travelers' diarrhea, while either increasing intake of fluids only or loperamide or bismuth subsalicylate may suffice for most cases of mild diarrhea. Further studies are needed to address knowledge gaps regarding optimal therapies, the individual, community and global health risks of MDR acquisition, manipulation of the microbiome in prevention and treatment and the utility of laboratory testing in returning travelers with persistent diarrhea.

Epidemiology of travellers' diarrhea

BACKGROUND

Travellers' diarrhea (TD) continues to be the most frequent health problem in travellers with destinations in lower income parts of the world as compared with where they reside, even if that risk has slightly decreased.

METHODS

A systematic review was published 18 months ago; now PubMed was searched for more recent publications relating to travel, diarrhea, epidemiology, incidence, risk.

RESULTS

A trend to decreasing incidence rates have been noted in this as compared with the last century, but TD remains frequent. The clinical picture varies from a trivial ailment to severe with subsequent hospitalization. Of great concern are long-term sequelae, particularly post-infectious irritable bowel syndrome. The most important risk factors are the destination and duration of exposure among the environmental factors, whereas the age is the most relevant host factor.

CONCLUSIONS

Even if improved hygienic conditions in low-income countries often visited by travellers have resulted in slightly diminished incidence rates of TD, this remains a frequent health problem. Visitors to such destinations must be informed about that health risk and it is beneficial to equip them with instructions and a travel kit to enable them to some extent self-manage TD occurring abroad.

Systematic review of loperamide: No proof of antibiotics being superior to loperamide in treatment of mild/moderate travellers' diarrhoea

Looking at the worldwide emergency of antimicrobial resistance, international travellers appear to have a central role in spreading the bacteria across the globe. Travellers' diarrhoea (TD) is the most common disease encountered by visitors to the (sub)tropics. Both TD and its treatment with antibiotics have proved significant independent risk factors of colonization by resistant intestinal bacteria while travelling. Travellers should therefore be given preventive advice regarding TD and cautioned about taking antibiotics: mild or moderate TD does not require antibiotics. Logical alternatives are medications with effects on gastrointestinal function, such as loperamide. The present review explores literature on loperamide in treating TD. Adhering to manufacturer's dosage recommendations, loperamide offers a safe and effective alternative for relieving mild and moderate symptoms. Moreover, loperamide taken singly does no predispose to contracting MDR bacteria. Most importantly, we found no proof that would show antibiotics to be significantly more effective than loperamide in treating mild/moderate TD.

Prospective study of pathogens in asymptomatic travellers and those with diarrhoea: aetiological agents revisited

Travellers' diarrhoea (TD) remains the most frequent health problem encountered by visitors to the (sub)tropics. Traditional stool culture identifies the pathogen in only 15% of cases. Exploiting PCR-based methods, we investigated TD pathogens with a focus on asymptomatic travellers and severity of symptoms. Pre- and post-travel stools of 382 travellers with no history of antibiotic use during travel were analysed with a multiplex quantitative PCR for Salmonella, Yersinia, Campylobacter, Shigella, Vibrio cholerae and five diarrhoeagenic Escherichia coli: enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC) and enteroinvasive (EIEC). The participants were categorized by presence/absence of TD during travel and on return, and by severity of symptoms. A pathogen was indentified in 61% of the asymptomatic travellers, 83% of those with resolved TD, and 83% of those with ongoing TD; 25%, 43% and 53% had multiple pathogens, respectively. EPEC, EAEC, ETEC and Campylobacter associated especially with ongoing TD symptoms. EAEC and EPEC proved more common than ETEC. To conclude, modern methodology challenges our perception of stool pathogens: all pathogens were common both in asymptomatic and symptomatic travellers. TD has a multibacterial nature, but diarrhoeal symptoms mostly associate with EAEC, EPEC, ETEC and Campylobacter.

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.

Traveler's Diarrhea in Foreign Travelers in Southeast Asia: A Cross-Sectional Survey Study in Bangkok, Thailand

The effect of origin and destination country on traveler's diarrhea incidence rates in Southeast Asia is poorly understood, and research generally only addresses diarrhea in travelers from the developed world. This study evaluated the attack rate and effects of traveler's diarrhea by origin and destination and analyzed key risk factors. A self-administered questionnaire was provided to foreign travelers departing Southeast Asia from Suvarnabhumi Airport, Bangkok, Thailand. It evaluated traveler demographics, relevant knowledge and practices, experiences of diarrhea, and the details and consequences of each diarrheal episode. A total of 7,963 questionnaires were completed between April 2010 and July 2011. Respondents were 56% male (mean age 35) with a mean and median duration of stay of 28 days and 10 days, respectively. Most respondents were from Europe (36.8%) or East Asia (33.4%). The attack rate of traveler's diarrhea was 16.1%, with an incidence rate of 32.05 per 100 person months. Travelers' origin and destination countries significantly related to diarrhea risk. Oceanians had the highest risk (32.9%) and East Asians the lowest (2.6%). Vietnam and Indonesia were the highest risk destinations (19.3%). Other significant factors were youth, trip duration, number of countries visited, and frequently drinking beverages with ice.

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.

Vaccine-preventable travel health risks: what is the evidence--what are the gaps?

BACKGROUND

Existing travel health guidelines are based on a variety of data with underpinning evidence ranging from high-quality randomized controlled trials to best estimates from expert opinion. For strategic guidance and to set overall priorities, data about average risk are useful. The World Health Organization (WHO) plans to base future editions of "International Travel and Health" on its new "Handbook for Guideline Development."

METHODS

Based on a systematic search in PubMed, the existing evidence and quality of data on vaccine-preventable disease (VPD) risks in travelers was examined and essentials of vaccine efficacy were briefly reviewed. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework was used to evaluate the quality of the data.

RESULTS

Moderate-quality data to determine the risk of VPD exist on those that are frequently imported, whereas in most others the level of confidence with existing data is low or very low.

CONCLUSIONS

In order for the WHO to produce graded risk statements in the updated version of "International Travel and Health," major investment of time plus additional high-quality, generalizable risk data are needed.

Potential drug interactions in travelers with chronic illnesses: a large retrospective cohort study

BACKGROUND

Data regarding the prevalence of potential interactions between travel-related medications (TRM) and chronic medications in use, or medical conditions of travelers to developing countries are limited.

METHODS

A retrospective cohort study of travelers to low income countries. We extracted data on demographics, travel destinations, use of chronic medications, drug allergies, and relevant medical conditions. The following TRM were evaluated: mefloquine, primaquine, doxycycline, atovaquone/proguanil, fluoroquinolone antibiotics, rifaximin, azithromycin, and acetazolamide.

RESULTS

A total of 16,263 travelers were included in the analysis, of whom 3299(20%) suffered from chronic illnesses and 2316(14%) reported chronic medication use. A potential drug-drug interaction with TRM was identified in 1047(45%) of travelers using chronic medication. Fluoroquinolones and azithromycin were the most commonly implicated TRMs. A potential medical condition interaction with TRM was identified in 717(22%) of travelers having chronic illnesses. acetazolamide, primaquine and mefloquine, were the most commonly TRMs implicated. Drug allergies, which can pose a relative contraindication for use of acetazolamide, were reported by 1323(8.1%) of all travelers.

CONCLUSIONS

Potential drug-drug and drug-disease interactions involving TRM might occur in a significant proportion of travelers with chronic medical conditions. Education of health practitioners regarding such potential drug interactions and caution when in prescribing travel-related medications is warranted.

Expatriates: special considerations in pretravel preparation

Expatriates comprise a diverse set of travelers who face unique medical, psychiatric, and non-health-related risks as a result of increased exposure to host country environment and associated lifestyle. Expatriates have an increased risk of developing malaria, gastrointestinal disorders, latent tuberculosis, vaccine-preventable infections, and psychological disorders, when compared with other travelers, yet the majority of existing pretravel guidelines have been designed to suit the needs of nonexpatriates. Although greater interest in expatriate health issues has led to improved characterization of illness in this population, expatriate-specific risk mitigation strategies-including modifications to chemoprophylaxis recommendations, limiting tuberculosis exposure, and prevention of occupational or sexual blood-borne virus transmission-are poorly described. Occupations and destinations affect travel-related disease risk and should inform the pretravel consultation.

The immunosuppressed traveler

This article reviews the normal immune response to vaccines. It describes the effect of different immunosuppressive therapies (glucocorticoids, inhibitors of calcineurin and mTOR, azathioprine, mycophenolate acid, methotrexate, depleting and nondepleting monoclonal antibodies, and tumor necrosis factor antagonists) on critical steps in the cellular and humoral immune responses to vaccines. The impact of age-related involution of thymus and bone marrow on the immune reconstitution in allogeneic hematopoietic cell transplant recipients and human immunodeficiency virus is covered. A practical approach to vaccinating and preparing travelers with severe immunosuppression is proposed.