Self-reported illness among Boston-area international travelers: A prospective study

Influenza: seasonality and travel-related considerations

RATIONALE FOR REVIEW

This review aims to summarize the transmission patterns of influenza, its seasonality in different parts of the globe, air travel- and cruise ship-related influenza infections and interventions to reduce transmission.

KEY FINDINGS

The seasonality of influenza varies globally, with peak periods occurring mainly between October and April in the northern hemisphere (NH) and between April and October in the southern hemisphere (SH) in temperate climate zones. However, influenza seasonality is significantly more variable in the tropics. Influenza is one of the most common travel-related, vaccine-preventable diseases and can be contracted during travel, such as during a cruise or through air travel. Additionally, travellers can come into contact with people from regions with ongoing influenza transmission. Current influenza immunization schedules in the NH and SH leave individuals susceptible during their respective spring and summer months if they travel to the other hemisphere during that time.

CONCLUSIONS/RECOMMENDATIONS

The differences in influenza seasonality between hemispheres have substantial implications for the effectiveness of influenza vaccination of travellers. Health care providers should be aware of influenza activity when patients report travel plans, and they should provide alerts and advise on prevention, diagnostic and treatment options. To mitigate the risk of travel-related influenza, interventions include antivirals for self-treatment (in combination with the use of rapid self-tests), extending the shelf life of influenza vaccines to enable immunization during the summer months for international travellers and allowing access to the influenza vaccine used in the opposite hemisphere as a travel-related vaccine. With the currently available vaccines, the most important preventive measure involves optimizing the seasonal influenza vaccination. It is also imperative that influenza is recognized as a travel-related illness among both travellers and health care professionals.

Healthcare seeking during travel: an analysis by the GeoSentinel surveillance network of travel medicine providers

BACKGROUND

International travellers may seek care abroad to address health problems that arise during their trip or plan healthcare outside their country of residence as medical tourists.

METHODS

Data were collected on travellers evaluated at GeoSentinel Network sites who reported healthcare during travel. Both unplanned and planned healthcare were analysed, including the reason and nature of healthcare sought, characteristics of the treatment provided and outcomes. Travellers that presented for rabies post-exposure prophylaxis were described elsewhere and were excluded from detailed analysis.

RESULTS

From May 2017 through June 2020, after excluding travellers obtaining rabies post-exposure prophylaxis (n= 415), 1093 travellers reported care for a medical or dental issue that was an unanticipated part of the travellers' planned itinerary (unplanned healthcare). Travellers who sought unplanned healthcare abroad had frequent diagnoses of acute diarrhoea, dengue, falciparum malaria and unspecified viral syndrome, and obtained care in 131 countries. Thirty-four (3%) reported subsequent deterioration and 230 (21%) reported no change in condition; a third (n = 405; 37%) had a pre-travel health encounter. Forty-one travellers had sufficient data on planned healthcare abroad for analysis. The most common destinations were the US, France, Dominican Republic, Belgium and Mexico. The top reasons for their planned healthcare abroad were unavailability of procedure at home (n = 9; 19%), expertise abroad (n = 9; 19%), lower cost (n = 8; 17%) and convenience (n = 7; 15%); a third (n = 13; 32%) reported cosmetic or surgical procedures. Early and late complications occurred in 14 (33%) and 4 (10%) travellers, respectively. Four travellers (10%) had a pre-travel health encounter.

CONCLUSIONS

International travellers encounter health problems during travel that often could be prevented by pre-travel consultation. Travellers obtaining planned healthcare abroad can experience negative health consequences associated with treatments abroad, for which pre-travel consultations could provide advice and potentially help to prevent complications.

Dimensions of the health benefits of wellness tourism: A review

The benefits of wellness tourism have been recently noted by researchers and industry representatives. This study examined the health dimensions of these benefits posited by a large array of interdisciplinary studies from 2002 up to the present. Open coding was used to conduct an inductive evaluation to classify these health benefits. Results showed four main dimensions, namely, physical fitness, psychological fitness, quality of life (QOL), and environmental health; however, these dimensions need further investigation. Physiological health benefits can also be demonstrated through future experiments, which can further focus on empirical research on the psychological benefits and its overall effect on the QOL. This study contributes to the current literature by providing novel theoretical foundations and subsequently aids practitioners to understand customers better and convey their marketing messages to tourists more effectively.

Effects of sanitation and hygiene perceptions on international travelers' health, travel plans and trip experiences in India

Background

International travelers often experience travelers' diarrhea. However, there is paucity of data on whether self-reported gastrointestinal symptoms influence travelers' perceptions of adequacy of sanitation and hygiene services encountered during travel, and to what degree their travel plans, and overall trip experience are impacted.

Methods

A cross-sectional face-to-face survey was conducted amongst international travelers in India. Data collected included socio-demographics, travel characteristics, self-reported occurrence and frequency/severity of gastrointestinal symptoms, perceptions of sanitation and hygiene encountered, and adverse effects of symptoms on travel plans and trip experiences. Chi-square tests and logistic regression were performed to describe differences and associations between categorical variables.

Results

Of the 300 international travelers surveyed, 46.3% experienced diarrhea. At least two thirds of travelers perceived the quality of sanitation (67.0%) and hygiene (70.0%) encountered to be inadequate. Perceptions of inadequate sanitation (adjusted OR = 3.0; 95% CI 1.7-5.5) and poor hygiene (adjusted OR = 7.7; 95% CI 4.1-15.5) were higher among travelers who experienced diarrhea. Additionally, both higher likelihood of travel plans being affected (adjusted OR = 10.7; 95% CI 5.1-23.6) and adverse impacts on overall trip experience (adjusted OR = 2.8; 95% CI 1.4-5.8) were reported among those who experienced diarrhea.

Conclusions

More than two thirds of travelers surveyed in India experienced inadequate sanitation and hygiene services, with perceptions influenced by occurrence and frequency of diarrhea. Self-reported diarrhea was also associated with adverse effects on travel plans and overall trip experience. While these results may seem intuitive, they have important implications and suggest that improving sanitation and hygiene standards in India could potentially enhance tourism.

Incidence Rate and Risk Factors Associated with Travelers' Diarrhea in International Travelers Departing from Utah, USA

Despite knowledge on the causes and prevention strategies for travelers' diarrhea (TD), it continues to be one of the most common illnesses experienced by U.S. international travelers. However, studies of risk factors associated with TD among U.S. travelers are limited. In this study, we aimed to determine the incidence rate of TD, the proportion of travelers who experience TD, and to identify risk factors associated with TD. In this cross-sectional study, we collected and analyzed data from anonymous posttravel questionnaires submitted by international travelers recruited during their pretravel visit at two travel clinics in Salt Lake City, Utah, from October 2016 to March 2020. Of 571 travelers who completed posttravel surveys, 484 (85%) answered the TD question, of which 111 (23%) reported TD, for an incidence rate of 1.1 episodes per 100 travel-days (95% confidence interval [CI]: 0.9-1.4). In a multivariable model, visiting Southeast Asian (odds ratio [OR]: 2.60; 95% CI: 1.45-4.72) and African (OR: 2.06; 95% CI: 1.09-3.93]) WHO regions, having 10 or more individuals in the group (OR: 3.91; 95% CI: 1.50-11.32]), longer trip duration (OR: 1.01; 95% CI: 1.00-1.02), visiting both urban and rural destinations (OR: 1.94; 95% CI: 1.01-3.90), and taking medications/supplements to prevent TD (OR: 2.74; 95% CI: 1.69-4.47) were statistically significantly associated with increased odds of reporting TD. TD continues to be common in international travelers from the United States. Our findings provide insights regarding travelers' behaviors regarding TD in international travelers from high-income countries and shows the need for additional research into prevention strategies for travelers' diarrhea.

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.

Telemedicine for international travelers through a Smartphone-based monitoring platform (Trip Doctor®)

BACKGROUND

Overall, more than 50% of international travelers develop symptoms while traveling and 55% of them seek medical assistance during the trip. We conducted a study to evaluate the usefulness of a Smartphone app called TRIP Doctor® to provide telemedicine to international travelers.

METHODS

Participants over 18 years old attending our travel clinic at Hospital Clinic in Barcelona were invited to participate during 2017-2019. After downloading the app, the health status of the traveler was monitored on a daily basis, providing specific medical advice and offering remote contact with specialized physicians through an integrated chat, if needed.

RESULTS

From 449 users, 59 (13%) contacted for medical assistance through the app during the trip. Main reasons for telemedicine were diarrhea (25.7%), skin conditions (19.7%) and fever (12.1%). Among patients who contacted, 90% of the travelers did not require to be referred to a local doctor. Symptomatic treatment was the main treatment prescribed (38%). In a 14.7% of the cases a follow-up was not required, a 63.2% recovered and 22.1% were loss of follow-up. After a multivariate analysis, duration of trip >14 days was found to be the only factor associated with the use of telemedicine (OR 2.2, CI 95% 1.1-4.5, p = 0.03).

CONCLUSION

In conclusion, travelers using telemedicine travelled for longer periods of time and mostly contacted for mild symptoms which could be solved successfully by remote assistance with our specialized doctors.

Hospital-based care and/or death followed by repatriation in Dutch travelers: The HAZARD study

BACKGROUND

Travelers can experience health problems while abroad. This descriptive study aimed to quantify the disease burden leading to hospital-based care, repatriation or death in Dutch travelers during a stay in a foreign country, including Europe.

METHODS

Retrospective study of demographic and clinical data from three medical assistance centers (MACs) and the Dutch Ministry of Foreign Affairs on Dutch travelers receiving hospital-based care or who died abroad in the years 2010-2014. Diagnoses were coded according to the International Classification of Diseases (ICD) and classified using the Global Burden of Disease tool.

RESULTS

Data was available for 77,741 travelers' incidents: 75,385 medical consultations and 2356 deaths. Four in five travelers received inpatient care, of which 36% concerned older travelers (65+) who had significantly longer hospital stays. Overall the top three diagnoses were: injuries (29%), infectious diseases (17%), and cardiovascular diseases (17%). Mental illness was reported in nearly 1.5% of the travelers. Incidence proportions were highest in South-Eastern Asia, with enteric infections as most common diagnosis. Injuries and communicable diseases occurred most often in South-Eastern Asia, while non-communicable diseases were mostly reported in South America. One in five travelers who consulted a physician was repatriated back home, mostly on a scheduled flight with or without medical escort. Cardiovascular diseases and injuries were the leading causes of death.

CONCLUSIONS

Not only communicable diseases, but also injuries and chronic diseases (in particular cardiovascular diseases) frequently affected travelers' health while staying abroad and frequently necessitated hospital-based care. This should be addressed during the pre-travel counseling.

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.

If I told you that there is no need for yellow fever vaccine booster would you still come to the travel clinic?: a cross-sectional study

Background

Yellow Fever (YF) immunization required a single dose vaccine with boosters every 10 years. After International Health Regulation (IHR) amendment annex 7 (July 2016), it was accepted that a single dose confers lifelong immunity. Since pre-travel advice is as important as vaccination when traveling, it is essential to clarify why travelers come to a travel health consultation, with the possibility of IHR amendment having a negative impact on travelers’ health. This study aims to describe travelers’ reasons to come to a pre-travel consultation in Lisbon and if they would return if they wouldn’t need the YF vaccine booster.

Methods

An observational cross-sectional study was conducted during 5 months in the waiting room of Instituto de Higiene e Medicina Tropical travel clinic in Lisbon, Portugal. Travelers were asked about sociodemographic characteristics, destination country, travel duration and reasons to travel in an anonymous self-administered questionnaire.

Results

A total of 1043 travelers agreed to participate in the study. Although 61.0% (627/1028) did not come to the clinic to get the YF vaccine, from those who did, 36.7% (133/362) would not come and 12.9% (47/362) didn’t knew if they would come if the vaccine would not be necessary.

Conclusion

The IHR amendment may have a negative impact on travel clinic attendance and on travelers´ health.

No time to die: An in-depth analysis of James Bond's exposure to infectious agents

Global travelers, whether tourists or secret agents, are exposed to a smörgåsbord of infectious agents. We hypothesized that agents pre-occupied with espionage and counterterrorism may, at their peril, fail to correctly prioritize travel medicine. To examine our hypothesis, we examined adherence to international travel advice during the 86 international journeys that James Bond was observed to undertake in feature films spanning 1962-2021. Scrutinizing these missions involved ∼3113 min of evening hours per author that could easily have been spent on more pressing societal issues. We uncovered above-average sexual activity, often without sufficient time for an exchange of sexual history, with a remarkably high mortality among Bond's sexual partners (27.1; 95% confidence interval 16.4-40.3). Given how inopportune a bout of diarrhea would be in the midst of world-saving action, it is striking that Bond is seen washing his hands on only two occasions, despite numerous exposures to foodborne pathogens. We hypothesize that his foolhardy courage, sometimes purposefully eliciting life-threatening situations, might even be a consequence of Toxoplasmosis. Bond's approach to vector-borne diseases and neglected tropical diseases is erratic, sometimes following travel advice to the letter, but more often dwelling on the side of complete ignorance. Given the limited time Bond receives to prepare for missions, we urgently ask his employer MI6 to take its responsibility seriously. We only live once.

Travel-Related Risk Behaviors and Antibiotic Use Among Older Travelers

Background

Antibiotic stewardship in the pretravel care of older adults is important to effectively treat infections while minimizing harm from side effects and unnecessary antibiotic use. The objective of this study was to compare the characteristics, risk behaviors, infectious diseases, and antibiotic use between older (≥60 years) and younger (18-59 years) travelers.

Methods

TravMil is a prospective, observational cohort of United States (US) Department of Defense beneficiaries traveling outside the continental US for ≤6.5 months. For this analysis, we included adults enrolled pretravel between January 2010 and August 2018 and excluded active duty personnel on deployment. Pre and post-travel surveys captured trip characteristics, exposures, illnesses, and antibiotic use.

Results

A total of 1742 travelers were analyzed: 747 (42.9%) were aged ≥60 years and 995 (57.1%) were aged 18-59 years. Older travelers were less likely to engage in high-risk dietary behaviors and experience travelers' diarrhea than younger travelers (18.2% vs 22.9%; P < .05). Influenza-like illness (12.5%) and febrile illness (3.4%) occurred less frequently in the older cohort. Antibiotic use for self-treatment was common in both age groups (25.7% vs 26.7%) and often inappropriate, for example, for treatment of occasional loose stool or mild travelers' diarrhea (67.0% [67/100] in older adults vs 57.6% [83/144] in younger adults; P < .05), and influenza-like illness (63.4% [64/101] vs 58.6% [68/116], respectively; P < .05).

Conclusions

Older travelers were less likely to engage in high-risk behaviors and experience travelers' diarrhea, and both age groups experienced mild, self-limited infections. Inappropriate use of antibiotics was common, suggesting that antimicrobial stewardship should be emphasized at pretravel counseling with international travelers.

An Investigation of the General Population's Self-Reported Hand Hygiene Behaviour and Compliance in a Cross-European Setting

Every year, thousands of people from the UK travel to other countries for work and leisure. Europe, and particularly Spain, is one of the most popular travel destinations for people from the UK. However, it is known that travel to other countries can enhance the risk of communicable disease transmission from person to person, especially when a new one emerges. Adequate hand hygiene behaviour and compliance is widely accepted as being a simple, effective method in preventing the spread of communicable diseases that may be contracted during travel abroad. There is a well-established body of work investigating hand hygiene practice and compliance in community settings, but no recent studies have examined the hand hygiene practice and compliance of the general population when travelling abroad or in a cross-European context. The findings of this study indicated that most UK members of the general population when travelling abroad have a good level of understanding of the importance of adequate hand hygiene practice and compliance and its role regarding communicable disease prevention and control. As such, self-reported levels of compliance were high. Similar findings were made for Spanish members of the general population. However, while self-reported perceptions of adequacy of hand hygiene performance were relatively high, particularly among UK respondents, this was not supported by responses specifically focused on hand hygiene behaviour. However, differences in self-reported adequacy regarding the importance of handwashing versus hand drying, the number of steps that should be followed and the length of time that should be spent washing and drying hands were found for each group. This suggests that self-reported compliance may reflect intention to practice hand hygiene rather than true compliance. It also suggests that there are gaps in knowledge regarding the adequate method of hand hygiene among the cohort as a whole, and indeed these differences may account be a factor in for the high transmission rates of communicable disease when travelling abroad.

Travellers' risk behaviors and health problems: Post-travel follow up in two travel medicine centers in Italy

OBJECTIVES

We examined the association between travellers' characteristics, compliance with pre-travel recommendations and health problems.

METHODS

Volunteer travellers were enrolled and data collected using a questionnaire between 30-60 days after returning home. We analyzed the associations through bivariate and multivariate models.

RESULTS

Of the 468 enrolled travelers, 68% consumed raw food and 81% food containing milk and/or eggs. 32% consumed street vendor food and 30% drinks containing ice. 24% used the recommended mechanical prophylaxis measures. 46% got sick during and/or after travel (gastrointestinal symptoms most frequently). Factors predisposing to health problems were female gender, youth/middle age, intermediate travel duration and profession. The American continent and staying in hostels and tents were significantly associated with febrile illness. Street vendor food was significantly associated with skin reactions.

CONCLUSIONS

Adherence to behavioral recommendations remains low. Travellers must be informed of health risks during and after travel.

New Tools to Test Stool: Managing Travelers' Diarrhea in the Era of Molecular Diagnostics

Travelers' diarrhea affects up to 60% of visitors to tropical and subtropical regions. Although symptoms are generally self-limited, some infections are associated with significant morbidity and occasional mortality. Newer molecular diagnostic techniques allow for highly sensitive, specific, and expeditious testing of a wide range of potential pathogens. Identification of the causative pathogen of travelers' diarrhea allows for targeted therapy and management and a reduction in empiric broad-spectrum coverage.

Traveler's diarrhea in children: New insights and existing gaps

The number of children accompanying their parents in international travel is increasing steadily, and with the rising global migration, children more frequently accompany their parents or caregivers for visiting friends or relatives (VFR). As compared to travel for tourism, VFR children are at higher risk of acquiring local diseases, as they more often stay in rural areas in resource-poor locations, have longer periods of visit, are less likely to attend pre-travel consultations, and less frequently adhere to recommended precautions. Travelers's diarrhea (TD) is the most common travel-associated illnesses in children. This review updates the existing knowledge on TD in children, regarding its distinctive epidemiology, risk factors, preventive measures, clinical manifestations, complications, causative microorganisms and management. Despite the limited focused research on pediatric TD, which challenges the formulation of children-oriented evidence-based guidelines, practical recommendations are suggested.

Travel-related health events and their risk factors in HIV-infected sub-Saharan migrants living in France and visiting their native country: The ANRS VIHVO cohort study

BACKGROUND

Literature on health events in HIV-infected travellers is scarce, particularly in sub-Saharan African (SSA) migrants.

METHODS

We investigated health events in HIV-infected SSA migrants living in France during and after travel to their native country. All had a pre-travel plasma viral load (pVL) below 200 copies/mL and were on stable combined antiretroviral therapy (cART). Logistic regression models were used to assess the risk factors for at least one adverse health event or febrile event.

RESULTS

Among 264 HIV migrants, pre-travel median CD4 count was 439/mm3 and 27 migrants (6%) experienced a low-level viremia between 50 and 200 copies/mL. One hundred (38%) experienced at least one event (13 experienced two events). The most common events were gastrointestinal, including diarrhoea (n = 29, 26%), respiratory events (n = 20, 18%), and malaria (n = 17, 15%; 1 death). In multivariable analysis, a pre-travel low-level viremia and a lack of pre-travel medical advice significantly increased the risk for any event (OR 4.31, 95% CI, 1.41-13.1; and OR 3.62, 95% CI, 1.38-9.47; respectively). A lack of pre-travel advice significantly increased the risk for febrile event.

CONCLUSIONS

Early and tailored counselling on pre-travel medical advice regarding diarrhoea and vector-borne diseases prophylactic measures in HIV-infected SSA migrants should be emphasised before travel to Africa.

Influenza vaccination coverage among US-Mexico land border crossers: 2009 H1N1 pandemic and 2011-2012 influenza season

BACKGROUND

The high volume of US-Mexico land border crossings can facilitate international dissemination of influenza viruses.

METHODS

We surveyed adult pedestrians crossing into the United States at two international land ports of entry to assess vaccination coverage during the 2009H1N1 influenza pandemic and 2011-2012 influenza season.

RESULTS

Of 559 participants in 2010, 23.4% reported receipt of the 2009H1N1 vaccine. Of 1423 participants in 2012, 33.7% received the 2011-2012 influenza vaccine. Both years, those crossing the border ≥8 times per month had lower vaccination coverage than those crossing less frequently. US-border residents had lower H1N1 coverage than those in other locations. Vaccination coverage was higher for persons age ≥65 years and, in 2010 only, those with less than high school education. Although most participants believed it is important to get vaccinated, only half believed the influenza vaccine was safe and effective. The main reasons for not receiving the influenza vaccine were beliefs of low risk of disease, time constraints, and concerns about vaccine safety (in 2010) or efficacy (in 2012).

CONCLUSIONS

International land border crossers are a large and unique category of travelers that require targeted binational strategies for influenza vaccination and education.

Infectious diseases acquired by international travellers visiting the USA

BACKGROUND

Estimates of travel-related illness have focused predominantly on populations from highly developed countries visiting low- or middle-income countries, yet travel to and within high-income countries is very frequent. Despite being a top international tourist destination, few sources describe the spectrum of infectious diseases acquired among travellers to the USA.

METHODS

We performed a descriptive analysis summarizing demographic and travel characteristics, and clinical diagnoses among non-US-resident international travellers seen during or after travel to the USA at a GeoSentinel clinic from 1 January 1997 through 31 December 2016.

RESULTS

There were 1222 ill non-US-resident travellers with 1393 diagnoses recorded during the 20-year analysis period. Median age was 40 (range 0-86 years); 52% were female. Patients visited from 63 countries and territories, most commonly Canada (31%), Germany (14%), France (9%) and Japan (7%). Travellers presented with a range of illnesses; skin and soft tissue infections of unspecified aetiology were the most frequently reported during travel (29 diagnoses, 14% of during-travel diagnoses); arthropod bite/sting was the most frequently reported after travel (173 diagnoses, 15% after-travel diagnoses). Lyme disease was the most frequently reported arthropod-borne disease after travel (42, 4%). Nonspecific respiratory, gastrointestinal and systemic infections were also among the most frequently reported diagnoses overall. Low-frequency illnesses (<2% of cases) made up over half of diagnoses during travel and 41% of diagnoses after travel, including 13 cases of coccidioidomycosis and mosquito-borne infections like West Nile, dengue and Zika virus diseases.

CONCLUSIONS

International travellers to the USA acquired a diverse array of mostly cosmopolitan infectious diseases, including nonspecific respiratory, gastrointestinal, dermatologic and systemic infections comparable to what has been reported among travellers to low- and middle-income countries. Clinicians should consider the specific health risks when preparing visitors to the USA and when evaluating and treating those who become ill.

Antibiotic resistance in travellers' diarrhoeal disease, an external perspective

BACKGROUND

There are many recommendations on the use of antibiotics for prophylaxis and treatment of travellers' diarrhoea (TD). As pharmacists with a special interest in antimicrobial stewardship, we examine and offer our perspective on advice that is recommended to travellers in terms of prevention, treatment and management of TD with a focus on antibiotic use and resistance.

METHODS

Publications on TD were identified through PubMed, Google Scholar and Cochrane Library databases searches using search terms 'travellers diarrhoea', 'travellers diarrhoea', 'travellers' diarrhoea' 'guidelines', 'expert opinion', 'expert reviews', 'South Asia' and 'South East Asia' (S and SE Asia), 'antibiotics', 'resistance genes', 'travel advice', 'pharmacists', 'guidelines', 'prevention' and 'treatment'. References of articles were also screened for additional relevant studies.

RESULTS

Whilst most guidelines and expert reviews were in agreement with the restricted use of antibiotics unless there was a clinical need, the literature review identified gaps in research into behaviours of travellers regarding non-compliance with the pre-travel advice provided and the need for in depth training and education for all healthcare professionals in providing 'tailored' advice for travellers going to high-risk destinations.

CONCLUSIONS

Travellers should be made aware of the problems of antimicrobial resistance in their destination and home countries and offered alternative forms of prophylaxis for TD. Strategies for prevention of TD, other than the use of antibiotics, also need to be emphasized. All healthcare professionals involved in giving advice about TD should be familiar with the epidemiology of the condition as this will inform responsible behaviours, risk assessment and management strategies in different geographical areas.

Approximate Bayesian algorithm to estimate the basic reproduction number in an influenza pandemic using arrival times of imported cases

BACKGROUND

In an influenza pandemic, arrival times of cases are a proxy of the epidemic size and disease transmissibility. Because of intense surveillance of travelers from infected countries, detection is more rapid and complete than on local surveillance. Travel information can provide a more reliable estimation of transmission parameters.

METHOD

We developed an Approximate Bayesian Computation algorithm to estimate the basic reproduction number (R₀) in addition to the reporting rate and unobserved epidemic start time, utilizing travel, and routine surveillance data in an influenza pandemic. A simulation was conducted to assess the sampling uncertainty. The estimation approach was further applied to the 2009 influenza A/H1N1 pandemic in Mexico as a case study.

RESULTS

In the simulations, we showed that the estimation approach was valid and reliable in different simulation settings. We also found estimates of R₀ and the reporting rate to be 1.37 (95% Credible Interval [CI]: 1.26-1.42) and 4.9% (95% CI: 0.1%-18%), respectively, in the 2009 influenza pandemic in Mexico, which were robust to variations in the fixed parameters. The estimated R₀ was consistent with that in the literature.

CONCLUSIONS

This method is useful for officials to obtain reliable estimates of disease transmissibility for strategic planning. We suggest that improvements to the flow of reporting for confirmed cases among patients arriving at different countries are required.

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.

Business travel-associated illness: a GeoSentinel analysis

Background

Analysis of a large cohort of business travelers will help clinicians focus on frequent and serious illnesses. We aimed to describe travel-related health problems in business travelers.

Methods

GeoSentinel Surveillance Network consists of 64 travel and tropical medicine clinics in 29 countries; descriptive analysis was performed on ill business travelers, defined as persons traveling for work, evaluated after international travel 1 January 1997 through 31 December 2014.

Results

Among 12 203 business travelers seen 1997-2014 (14 045 eligible diagnoses), the majority (97%) were adults aged 20-64 years; most (74%) reported from Western Europe or North America; two-thirds were male. Most (86%) were outpatients. Fewer than half (45%) reported a pre-travel healthcare encounter. Frequent regions of exposure were sub-Saharan Africa (37%), Southeast Asia (15%) and South Central Asia (14%). The most frequent diagnoses were malaria (9%), acute unspecified diarrhea (8%), viral syndrome (6%), acute bacterial diarrhea (5%) and chronic diarrhea (4%). Species was reported for 973 (90%) of 1079 patients with malaria, predominantly Plasmodium falciparum acquired in sub-Saharan Africa. Of 584 (54%) with malaria chemoprophylaxis information, 92% took none or incomplete courses. Thirteen deaths were reported, over half of which were due to malaria; others succumbed to pneumonia, typhoid fever, rabies, melioidosis and pyogenic abscess.

Conclusions

Diarrheal illness was a major cause of morbidity. Malaria contributed substantial morbidity and mortality, particularly among business travelers to sub-Saharan Africa. Underuse or non-use of chemoprophylaxis contributed to malaria cases. Deaths in business travelers could be reduced by improving adherence to malaria chemoprophylaxis and targeted vaccination for vaccine-preventable diseases. Pre-travel advice is indicated for business travelers and is currently under-utilized and needs improvement.

Real-time incidence of travel-related symptoms through a smartphone-based app remote monitoring system: a pilot study

Trip Doctor®, a Smartphone-based app monitoring system, was developed to detect infections among travelers in real-time. For testing, 106 participants were recruited (62.2% male, mean age 36 years (SD = 11)). Majority of trips were for tourism and main destinations were in South East Asia. Mean travel duration was 14 days (SD = 10). Diarrhea was the most frequently reported symptom (15.5%). The system demonstrated adequate usability and is ready to be used on a larger scale.

What proportion of international travellers acquire a travel-related illness? A review of the literature

INTRODUCTION

As international travel increases, travellers may be at increased risk of acquiring infectious diseases not endemic in their home countries. Many journal articles and reference books related to travel medicine cite that between 22-64% of international travellers become ill during or after travel; however, this information is minimal, outdated and limited by poor generalizability. We aim to provide a current and more accurate estimate of the proportion of international travellers who acquire a travel-related illness.

METHODS

We identified studies via PubMed or travel medicine experts, published between January 1, 1976-December 31, 2016 that included the number of international travellers acquiring a travel-related illness. We excluded studies that focused on a single disease or did not determine a rate based on the total number of travellers. We abstracted information on traveller demographics, trip specifics, study enrollment and follow-up and number of ill travellers and their illnesses.

RESULTS

Of 743 studies, nine met the inclusion criteria. The data sources were from North America (four studies) and Europe (five studies). Most travellers were tourists, the most frequent destination regions were Asia and Africa, and the median trip duration ranged from 8-21 days. Six studies enrolled participants at the travellers' pre-travel consultation. All studies collected data through either extraction from the medical record, weekly diaries, or pre- and post-travel questionnaires. Data collection timeframes varied by study. Between 6-87% of travellers became ill across all studies. Four studies provided the best estimate: between 43-79% of travellers who frequently visited developing nations (e.g. India, Tanzania, and Kenya) became ill; travellers most frequently reported diarrhoea.

CONCLUSION

This is the most comprehensive assessment available on the proportion of international travellers that develop a travel-related illness. Additional cohort studies would provide needed data to more precisely determine the rates of illness in international travellers.

KEYWORDS

International travel, travel, illness.

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.