Respiratory tract infections in travelers: a review of the GeoSentinel surveillance network

Pulmonary infections in the returning traveler

PURPOSE OF REVIEW

The recent COVID-19 pandemic has shaped the epidemiology of other infectious diseases globally. International tourist arrivals are increasing and recovering to prepandemic levels. This review focuses on respiratory infections in travelers, highlighting the characteristics of the main imported viral, bacterial, fungal, and parasitic infections with pulmonary involvement.

RECENT FINDINGS

A recent systematic review estimated a prevalence of respiratory symptoms in travelers of around 35%, increasing to nearly 65% in the context of mass gatherings. Common viral and bacterial pathogens account for the majority of respiratory infections with an identified cause; however, recent data focus on the need for surveillance of emerging infections such as MERS-CoV, henipaviruses and multidrug resistant bacteria, which may be spread through travel. Fungal and parasitic respiratory infections are less common, and acquisition is usually associated with specific risk factors or exposure in endemic areas. Special risk groups, such as immunocompromised travelers, may be particularly vulnerable, presenting with severe disease or reactivation of latent infections.

SUMMARY

The next significant international epidemic could involve another new infectious agent causing respiratory disease and spreading via mobile populations. Official protocols should be adhered to, and public health interventions implemented for effective control. Continued and globally coordinated investments in research for new vaccines, therapeutic agents, disease modeling, and digital tracking strategies are essential.

Characteristics of preventive intervention acceptance for international travel among clients aged 60 years and older from a Japanese multicenter pretravel consultation registry

OBJECTIVES

Pretravel consultation (PTC) is important for older adults owing to health problems associated with overseas travel. Although older adults in Japan, their PTC characteristics are less known. This study aimed to investigate the epidemiology of clients aged ≥ 60 years based on data from the Japan Pre-travel Consultation Registry (J-PRECOR).

METHODS

Clients aged ≥ 60 years who visited J-PRECOR cooperative hospitals from February 1, 2018, to May 31, 2022, were included. The primary endpoint was a comparison of prescriptions for vaccines for hepatitis A, tetanus toxoid, and malaria prophylaxis in travelers to high-risk malaria countries in yellow fever vaccination (YFV)-available facilities with and without YFV.

RESULTS

In total, 1000 clients (median age: 67 years) were included. Although 523 clients were immunized with YFV, only 38.6% of the 961 unimmunized clients were vaccinated with the tetanus toxoid-containing vaccine. Malaria chemoprophylaxis was prescribed to 25.7% of clients traveling for ≤55 days. At YFV-capable institutes, 557 clients traveling to yellow fever risk countries took PTC, 474 of whom received YFV and 83 were unvaccinated. Lower age (odds rate 0.85 per 1 year; 95% CI 0.80-0.90) and lower hepatitis A vaccination rate (0.29; 95% CI 0.14-0.63) were significantly associated with YFV.

CONCLUSIONS

Preventive interventions other than YFV should be offered to older adults.

Travel-related respiratory symptoms and infections in travellers (2000-22): a systematic review and meta-analysis

BACKGROUND

Respiratory tract infections (RTIs) are common in travellers due to the year-round or seasonal presence of respiratory pathogen and exposure to crowded environments during the itinerary. No study has systematically examined the burden of RTI infections among travellers. The aim of this systematic review and meta-analysis is to evaluate the prevalence of RTIs and symptoms suggestive of RTIs among travellers according to risk groups and/or geographic region, and to describe the spectrum of RTIs.

METHODS

The systematic review and meta-analysis was registered in PROSPERO (CRD42022311261). We searched Medline, Embase, Scopus, Cochrane Central, Web of Science, Science Direct and preprint servers MedRxiv, BioRxiv, SSRN and IEEE Xplore on 1 February 2022. Studies reporting RTIs or symptoms suggestive of RTIs in international travellers after 1 January 2000 were eligible. Data appraisal and extraction were performed by two authors, and proportional meta-analyses were used to obtain estimates of the prevalence of respiratory symptoms and RTIs in travellers and predefined risk groups.

FINDINGS

A total of 429 articles on travellers' illness were included. Included studies reported 86 841 symptoms suggestive of RTIs and 807 632 confirmed RTIs. Seventy-eight percent of reported respiratory symptoms and 60% of RTIs with available location data were acquired at mass gatherings events. Cough was the most common symptom suggestive of respiratory infections, and the upper respiratory tract was the most common site for RTIs in travellers. The prevalence of RTIs and respiratory symptoms suggestive of RTIs were 10% [8%; 14%] and 37% [27%; 48%], respectively, among travellers. Reporting of RTIs in travellers denoted by publication output was found to correlate with global waves of new respiratory infections.

INTERPRETATION

This study demonstrates a high burden of RTIs among travellers and indicates that travellers' RTIs reflect respiratory infection outbreaks. These findings have important implications for understanding and managing RTIs among travellers.

Effect of Omicron on the prevalence of COVID-19 in international travelers at the Mexico city international airport. December 16th, 2021 to January 31st, 2022

Introduction

SARS-CoV-2 continues to have a high rate of contagion worldwide. The new variant of concern, Omicron, has mutations that decrease the effectiveness of vaccines and evade antibodies from previous infections resulting in a fourth wave of the pandemic. It was identified in Mexico in December 2021.

Methods

The Traveler's Preventive Care Clinic from the Faculty of Medicine UNAM at Mexico City International Airport has performed rapid antigen and PCR SARS CoV2 tests since January 2021 to comply with the new travel requirements. Demographic and clinical characteristics were collected from each passenger and the fourth wave of the pandemic in Mexico mainly caused by Omicron was analyzed in the travelers.

Results

A total of 5176 travelers attended the clinic between the second half of December 2021 and January 2022. Ten percent of all the tests performed were positive (13% of PCR and 9.3% of antigens, p = 0.001). Most of the SARS CoV2 positive cases were asymptomatic (78%), with a ratio of 3.5:1 over the symptomatic. By age groups, this ratio was higher for those under 20 years old (8.7:1).

Discussion

This study shows the rapid escalation of positivity that occurred in Mexico, detected in travelers, from the second half of December 2020 and throughout the month of January 2021. The incidence of COVID-19 was extremely high in travelers who were mostly asymptomatic for the period under study.

Attitudes, practices, and obstacles towards influenza vaccination for international travelers among travel health advisors in Germany: A questionnaire-based survey

BACKGROUND

Influenza is the most frequent vaccine-preventable infection in travelers, and both national and international guidelines recommend considering seasonal influenza vaccination (SIV) not only for those with risk factors for complications but for all travelers. However, vaccination coverage may be hampered by a lack of awareness among travelers and health care providers and limited vaccine availability outside the local influenza season.

METHODS

We identified travel health advisors in databases of German medical professional societies and invited them to complete an online questionnaire between April and May 2021.

RESULTS

Among 1085 travel health advisors contacted by email, 253 (23.3%) completed the online questionnaire. Most of them recommend SIV for travelers older than 60 years or those with comorbidities regardless of the travel destination or the influenza season in Germany. However, only very few respondents stated that they had regular access to SIV in June (n = 16, 6.5%), July (n = 10, 4.0%), and August (n = 17, 6.9%), respectively. While most participants (n = 197, 79.4%) stated that they would vaccinate more travelers if they had SIV regularly available outside the German influenza season, only eleven respondents (4.4%) have previously ordered SIV produced for the southern hemisphere, which was attributed mainly to logistic barriers.

CONCLUSIONS

Travel health advisors in Germany recommend SIV for a considerable proportion of travelers. While most of them see a necessity to vaccinate throughout the year, availability of SIV outside the German season is very limited. Current organizational barriers must be overcome to increase vaccination coverage among international travelers.

Diagnostic tools for bacterial infections in travellers: Current and future options

International travel has increased dramatically over the past 50 years, and travel destinations have diversified. Although physicians are more familiar with the panel of aetiological agents responsible for illnesses of returning travellers, thanks to regular epidemiological studies, the spectrum of pathogens potentially encountered in various travel destinations is nevertheless increasing. In addition, the wide array of approaches currently available and addressed in this paper could render the procedures for microbiological analyses increasingly complex. As the time to result is crucial to adequately manage patients, modern approaches have been developed to shorten diagnosis delays. The syndromic approach, which consists of simultaneously testing a wide panel of microorganisms, substantially increases the diagnostic yield with significant time savings, particularly when coupled with point-of-care laboratories. The tools commonly used for this purpose are immunochromatographic tests, mainly targeting bacterial antigens, and multiplex real-time PCR. The emergence of next-generation sequencing technologies, which enable random amplification of genetic material of any microbe present in a clinical specimen, provides further exciting perspectives in the diagnosis of infectious diseases.

Impact of Doxycycline as Malaria Prophylaxis on Risk of Influenza-Like Illness among International Travelers

Travelers are often at risk for both influenza-like illness (ILI) and malaria. Doxycycline is active against pathogens causing ILI and is used for malaria prophylaxis. We evaluated the risk factors for ILI, and whether the choice of malaria prophylaxis was associated with ILI. TravMil is a prospective observational study enrolling subjects presenting to military travel clinics. Influenza-like illness was defined as subjective fever with either a sore throat or cough. Characteristics of trip and use of malaria prophylaxis were analyzed to determine association with development of ILI. Poisson regression models with robust error variance were used to estimate relative risk (RR) of ILI. A total of 3,227 trips were enrolled: 62.1% male, median age of 39 years (interquartile range [IQR] 27,59), median travel duration 19 days (IQR 12, 49); 32% traveled to Africa, 40% to Asia, and 27% to the Caribbean and Latin America. Military travel (46%) and vacation (40%) were most common reasons for travel. Among them, 20% took doxycycline, 50% other prophylaxis, and 30% took none; 8.7% developed ILI. Decreased RR of ILI was associated with doxycycline (RR 0.65 [0.43–0.99], P = 0.046) and military travel (RR 0.30 [0.21–0.43], P < 0.01). Increased risk of ILI was associated with female gender (RR 1.57 [1.24–1.98], P < 0.01), travel to Asia (RR 1.37 [1.08–1.75], P = 0.01), and cruises (RR 2.21 [1.73–2.83], P < 0.01). Use of doxycycline malaria prophylaxis is associated with a decreased risk of ILI. Possible reasons include anti-inflammatory or antimicrobial effects, or other unmeasured factors. With few strategies for decreasing ILI in travelers, these findings bear further investigation.

Redefining priorities towards graded travel-related infectious disease research

Our knowledge of the health problems and infections encountered by international travellers has evolved considerably in the past decades. The growth of global networks such as the GeoSentinel Surveillance network, TropNet Europe, EuroTravNet and networks based in North America have provided valuable information on the frequency of a wide array of travel-related diseases and accidents, including details on the destination of travel and trends over time. The information gained from these network studies has provided important data for the practice of travel medicine and in some instances for the development of practice guidelines. However, network data due to a lack of denominators usually cannot serve as a basis for a GRADE approach to guideline development. Although epidemiological network studies will continue to serve an important role in travel medicine we encourage an additional strong focus towards translational scientific research questions and towards the broader use of novel techniques to obtain more accurate epidemiological analyses to address the many unanswered questions in our field.

Bordetella pertussis infections in travelers: data from the GeoSentinel global network

BACKGROUND

Pertussis is a highly contagious, vaccine-preventable respiratory infection that is endemic worldwide. There are limited data regarding the occurrence of pertussis in travelers. The objective of this study is to identify travel-related pertussis cases reported to the GeoSentinel Surveillance Network.

METHODS

This is a descriptive, retrospective analysis of GeoSentinel records from 25 travel/tropical medicine clinics in 16 countries. Frequencies of demographic and travel-related characteristics and symptoms of 74 cases of pertussis in travelers and new immigrants from 1999 to 2015 were analysed.

RESULTS

There were 74 probable and confirmed cases of pertussis in the GeoSentinel database; median age was 44 years, and 38 (51%) patients were female. Tourism was the most common reason for travel (41; 55%). Country of exposure was determined in 66 cases with travelers returning from India and China constituting the highest number of cases (10 cases each; 15% each). Seventy of 74 (95%) patients had respiratory symptoms, while fatigue and fever were reported by 21 (28%) and 20 (27%), respectively. Immunization status against pertussis was unknown. Most cases were reported after 2005 (69; 93%).

CONCLUSIONS

Our study describes 74 cases of pertussis acquired during travel and reported to the GeoSentinel Network. Pertussis should be considered in returned travelers who present with respiratory symptoms. Surveillance and detection of imported cases are important to prevent onward transmission in the community. The pre-travel consultation provides an opportunity to verify immunization status and provide routine vaccinations such as pertussis.

Pulmonary infections in the returned traveller

Pulmonary infections in the returned traveller are a common presentation. A wide variety of infections may present with pulmonary symptoms. It is important for clinicians to differentiate the cause of these symptoms. The risk of contracting certain travel-related pulmonary diseases depends on travel destination, length of stay, activities undertaken and co-morbidities. Some pathogens are found worldwide, whilst others are related to specific locations. This review article will discuss the approach to diagnosing and treating pulmonary infections in the returned traveller.

A closer look at travellers' infections abroad: Finnish nationwide data with incidences, 2010 to 2012

BACKGROUND

Although infections represent the most common health problem of travellers abroad, data on morbidity and incidences of various infections are scarce.

METHOD

Data on infections of Finnish travellers during 2010-2012 were retrieved from the database of SOS International, an assistance organization covering 95% of Finns requiring aid abroad. The study included 30,086 cases. For incidence calculation, the data were linked to the numbers of Finns visiting these regions during the same period as recorded by the Official Statistics of Finland.

RESULTS

The incidence of infections was particularly high in Africa, southern Europe plus the eastern Mediterranean, and Asia plus Oceania. The most frequent diagnoses were acute gastroenteritis (38.0%) and respiratory-tract infections (RTI) (34.5%), followed by infections of the ear (12.6%), skin or subcutaneous tissue (5.1%), urogenital tract (4.2%), eye (3.1%), and systemic febrile infections (2.2%). Vaccine-preventable diseases (VPD) accounted for 0.8% of cases, with varicella as most (49%) and influenza as second-most (27%) common.

CONCLUSIONS

Incidence of infections was higher in southern than in eastern and western Europe. Gastroenteritis and RTI proved the most frequent diagnoses, whereas systemic febrile infections were uncommon. Despite pre-travel immunizations, VPDs still occurred; pre-travel consultation should cover both varicella and influenza.

Importance of a Travel History in Evaluation of Respiratory Infections

PURPOSE OF REVIEW

International travel has increased at a fast pace and will continue to rapidly rise. Concomitantly, with this increase in travel is the increase in post travel-related diseases, such as respiratory illnesses. Identifying the cause of the posttravel respiratory illness is a complex challenge for many healthcare professionals because similar presentations occur for both infectious and noninfectious causes. Not only is diagnosis important but also transmission prevention. In the last two decades, there have been several severe infectious respiratory syndromes that have spread through international travel causing epidemics in many countries.

RECENT FINDINGS

A detailed travel history with the chronology of symptoms paired with the patient's medical risk factors and exposures along with some basic knowledge of infectious respiratory illnesses will help facilitate clinical decision making. This framework will help create a broad, but appropriate differential diagnosis to guide clinical workup, prevent delays in diagnosis, and implement the appropriate precautions to prevent transmission if appropriate.

SUMMARY

The foundation to diagnosing a travel-related respiratory illness lies within integrating the patient's travel history, comorbid conditions, clinical presentation, exposures, and mode of transmission. A timely and accurate diagnosis benefits not only the patient but also the surrounding community to prevent further individual transmission, epidemics, and pandemics.

Management of septic shock and severe infections in migrants and returning travelers requiring critical care

During the past decade, global human movement created a virtually "borderless world". Consequently, the developed world is facing "forgotten" and now imported infectious diseases. Many infections are observed upon travel and migration, and the clinical spectrum is diverse, ranging from asymptomatic infection to severe septic shock. The severity of infection depends on the etiology and timeliness of diagnosis. While assessing the etiology of severe infection in travelers and migrants, it is important to acquire a detailed clinical history; geography, dates of travel, places visited, type of transportation, lay-overs and intermediate stops, potential exposure to exotic diseases, and activities that were undertaken during travelling and prophylaxis and vaccines either taken or not before travel are all important parameters. Tuberculosis, malaria, pneumonia, visceral leishmaniasis, enteric fever and hemorrhagic fever are the most common etiologies in severely infected travelers and migrants. The management of severe sepsis and septic shock in migrants and returning travelers requires a systematic approach in the evaluation of these patients based on travel history. Early and broad-spectrum therapy is recommended for the management of septic shock comprising broad spectrum antibiotics, source control, fluid therapy and hemodynamic support, corticosteroids, tight glycemic control, and organ support and monitoring. We here review the diagnostic and therapeutic routing of severely ill travelers and migrants, stratified by the nature of the infectious agents most often encountered among them.

Illness and injury of travellers abroad: Finnish nationwide data from 2010 to 2012, with incidences in various regions of the world

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Respiratory infections in travelers returning from the tropics

Respiratory tract infections (RTIs), beside diarrheas, skin lesions, and fevers of unknown origin, are one of the most common health problems acquired by travelers going to tropical and subtropical countries. Visitors to African, Asian, or South American destinations, typically characterized by harsh environmental conditions and poor sanitation standards, are at risk of exposure to a large number of pathogens causing infectious diseases. The infections are transmitted from contaminated food and water, through the air, direct contact, or by insects. The main modes of RTIs transmission include droplet infection and direct contact. The clinical spectrum of RTIs in travelers is broad, from upper respiratory tract infections, pharyngitis, bronchitis, pneumonia, to influenza-like illness. The spectrum of microbial agents causing respiratory infections include numerous viruses and bacteria, rarely fungi, and parasites. Most travelers complain of mild infections, only a small minority seek medical assistance and report to health care facilities. Because of the risk of importing pathogens into Europe or North America and transferring them onto the local population, it is important to present the scale of the problem in relation to rapid development of tourism industry and an increasing number of intercontinental journeys. The aim of the study was to discuss the occurrence of travel-related respiratory infections among representatives of temperate climate traveling to and returning from the tropics.

Analyzing GeoSentinel surveillance data: a comparison of methods to explore acute gastrointestinal illness among international travelers

GeoSentinel is a global surveillance network of travel medicine clinics that collect data from ill international travelers. Analyses have relied on proportionate morbidity calculations, but proportionate morbidity cannot estimate disease risk because healthy travelers are not included in the denominator. The authors evaluated the use of a case-control design, controlling for GeoSentinel site and date of clinic visit, to calculate a reporting odds ratio (ROR). The association between region of travel and acute gastrointestinal illness was evaluated. All analyses found that the association with acute gastrointestinal illness was greatest among those who traveled to North Africa and South-Central Asia. There was consistency in the magnitude of the ROR and proportionate morbidity ratio (PMR) in regions such as the Caribbean. However, in other regions, the matched ROR was noticeably different than the PMR. The case-control ROR may be preferred for single-disease/syndrome analytical studies using GeoSentinel surveillance data or other surveillance data.

Business travelers: vaccination considerations for this population

Illness in business travelers is associated with reduced productivity on the part of the employee as well as the employer. Immunizations offer a reliable method of preventing infectious diseases for international business travelers. The authors review the travel patterns of business travelers, available data on illnesses they encounter, their potential travel-associated risks for vaccine-preventable diseases and recommendations on immunizations for this population. Routine vaccines (e.g., measles, tetanus and influenza) should be reviewed to assure that they provide current coverage. The combined hepatitis A and hepatitis B vaccine with a rapid schedule offers options for those with time constraints. Other vaccine recommendations for business travelers need to focus on their destinations and activities and underlying health, taking into account the concept of cumulative risk for those with frequent travel, multiple trips or long stays.

Infections in travelers

Travel medicine continues to grow as international tourism and patient medical complexity increases. This article reflects the state of the current field, but new recommendations on immunizations, resistance patterns, and treatment modalities constantly change. The US Centers for Disease Control and the World Health Organization maintain helpful Web sites for both patient and physician. With thoughtful preparation and prevention, risks can be minimized and travel can continue as safely as possible.

Prevention of influenza among travellers attending at a UK travel clinic: beliefs and perceptions. A cross-sectional study

BACKGROUND

Travellers' compliance with measures to prevent influenza through the use of antivirals and influenza vaccine remains very poor despite influenza being one of the commonest travel and vaccine-preventable diseases. A study was undertaken to assess travellers' beliefs, perceptions and intentions to take antivirals for the treatment and prevention of influenza during the H1N1 pandemic.

METHODS

A cross-sectional survey (n = 96) of travellers who attended the Royal Free Travel Health Centre, London, UK was undertaken in September 2009. A self-administered questionnaire was completed by a traveller in advance of their pre-travel health consultation. Logistic regression identified variables independently associated with compliance.

RESULTS

Influenza vaccination uptake for the 5 years preceding the study was found to be 20·8%. This was statistically significantly higher for older travellers and those with underlying health conditions (P < 0·005). Mean intention to comply with antiviral drugs on a preventive and therapeutic basis was 58% and 72%, respectively, and this varied markedly with age and with dispensed antimalarial chemoprophylaxis.

CONCLUSION

This study identifies some beliefs and perceptions travellers consider with regard to the therapeutic and preventive influenza use of antivirals during the H1N1 pandemic; it underscores the importance of travellers receiving hemisphere appropriate influenza vaccination. The external validity of these study findings requires further corroboration involving other travel clinics and different cohorts of travellers during seasonal activity or outbreaks of influenza. These findings could guide the development of future strategies for the prevention of influenza in travellers.

Effect of travel on influenza epidemiology

To assess the attack and incidence rates for influenza virus infections, during October 2006-October 2007 we prospectively studied 1,190 adult short-term travelers from the Netherlands to tropical and subtropical countries. Participants donated blood samples before and after travel and kept a travel diary. The samples were serologically tested for the epidemic strains during the study period. The attack rate for all infections was 7% (86 travelers) and for influenza-like illness (ILI), 0.8%. The incidence rate for all infections was 8.9 per 100 person-months and for ILI, 0.9%. Risk factors for infection were birth in a non-Western country, age 55-64 years, and ILI. In 15 travelers with fever or ILI, influenza virus infection was serologically confirmed; 7 of these travelers were considered contagious or incubating the infection while traveling home. Given the large number of travelers to (sub)tropical countries, travel-related infection most likely contributes to importation and further influenza spread worldwide.

Travel-related infections in children

Malaria, diarrhea, respiratory infections, and cutaneous larva migrans are common travel-related infections observed in children and adolescents returning from trips to developing countries. Children visiting friends and relatives are at the highest risk because few visit travel clinics before travel, their stays are longer, and the sites they visit are more rural. Clinicians must be able to prepare their pediatric-age travelers before departure with preventive education, prophylactic and self-treating medications, and vaccinations. Familiarity with the clinical manifestations and treatment of travel-related infections will secure prompt and effective therapy.

Travel in patients receiving TNF-alpha inhibitors

The TNF-alpha inhibitors, infliximab (Remicade), etanercept (Enbrel) and adalimumab (Humira) are increasingly being used for chronic inflammatory diseases and have effectively allowed many patients to return to more active lifestyles. The impact of these agents on immune function has led to the recognition of specific infectious complications. The combination of the increasingly active lifestyles of those receiving these agents and their immunosuppressive effects pose new challenges for practitioners of travel medicine. The purpose of this article is to review the immunologic and infectious consequences of these therapies and their potential impact on travelers.

Travel-associated illness in older adults (>60 y)

BACKGROUND

Older individuals represent a substantial proportion of international travelers. Because of physiological changes and the increased probability of underlying medical conditions, older travelers might be at higher risk for at least some travel-associated diseases.

METHODS

With the aim of describing the epidemiology of travel-associated diseases in older adults, medical data were prospectively collected on ill international travelers presenting to GeoSentinel sites from 1997 to 2009. Seven thousand thirty-four patients aged 60 years and over were identified as older travelers and were compared to 56,042 patients aged 18-45 years, who were used as the young adult reference population.

RESULTS

The proportionate morbidity of several etiological diagnoses was higher in older ill travelers compared to younger ill, including notably lower respiratory tract infections, high-altitude pulmonary edema, phlebitis and pulmonary embolism, arthropod bites, severe malaria, rickettsiosis, gastritis, peptic ulcers, esophagitis and gastroesophageal reflux disease, trauma and injuries, urinary tract infections, heart disease, and death. In contrast, acute diarrhea, upper respiratory tract infections, flu and flu-like illnesses, malaria, dengue, genital infections, sexually transmitted diseases, and schistosomiasis proportionate morbidities were lower among the older group.

CONCLUSION

Older ill travelers are more likely to suffer from certain life-threatening diseases and would benefit from reinforcement of specific preventive measures including use of anti-thrombosis compression stockings and sufficient hydration and exercises during long-distance flights, hand hygiene, use of disposable handkerchiefs, consideration of face-masks in crowded conditions, influenza and pneumococcal vaccines, progressive acclimatization to altitude, consideration of acetazolamide, and use of repellents and mosquito nets. Antibiotics for the presumptive treatment of respiratory and urinary tract infections may be considered, as well as antacid medications. At-risk patients should be referred to a specialist for medical evaluation before departing, and optimal control of co-morbidities such as cardiovascular and chronic obstructive pulmonary diseases should be achieved, particularly for high-altitude travel.

Clinical and microbiological evaluation of travel-associated respiratory tract infections in travelers returning from countries affected by pandemic A(H1N1) 2009 influenza

BACKGROUND

Although acute respiratory tract infections (RTI) have been recognized as a significant cause of illness in returning travelers, few studies have specifically evaluated the etiologies of RTI in this population.

METHODS

This prospective investigation evaluated travelers returning from countries with endemic influenza A(H1N1) 2009, and who were seen in our department at the onset of the outbreak (April-July 2009). Patients were included if they presented with signs of RTI that occurred during travel or less than 7 days after return from overseas travel. Patients were evaluated for microbial agents with RespiFinder plus assay, and throat culture according to clinical presentation.

RESULTS

A total of 113 travelers (M/F ratio 1.2:1; mean age 39 y) were included. They were mainly tourists (n = 50; 44.2%) mostly returning from North America (n = 65; 58%) and Mexico (n = 21; 18.5%). The median duration of travel was 23 days (range 2-540 d). The median lag time between return and onset of illness was 0.2 days (range 10 d prior to 7 d after). The main clinical presentation of RTI was influenza-like illness (n = 76; 67.3%). Among the 99 microbiologically evaluated patients, a pathogen was found by polymerase chain reaction (PCR) or throat culture in 65 patients (65.6%). The main etiological agents were influenza A(H1N1) 2009 (18%), influenza viruses (14%), and rhinovirus (20%). A univariate analysis was unable to show variables associated with influenza A(H1N1) 2009, whereas rhinorrhea was associated with viruses other than influenza (p = 0.04).

CONCLUSION

Despite the A(H1N1) 2009 influenza pandemic, rhinovirus and other influenza viruses were also frequent causes of RTI in overseas travelers. Real-time reverse transcription-PCR and nasopharyngeal swab cultures are useful diagnostic tools for evaluating travelers with RTI.

Causes of death abroad: analysis of data on bodies returned for cremation to Scotland

BACKGROUND

The majority of travelers from the UK and Scotland visit Europe, particularly Spain and France, as well as North America, yet surveillance that aids in travel medicine guidance continues to focus on infectious diseases relating to developing countries. Here, we report on causes of death among all bodies returned to Scotland for cremation.

METHODS

Data collected by the Scottish Government on bodies being returned from abroad for cremation was collated for the period 2000 to 2004, and analyzed to identify the cause and location of death among travelers as well as to test the hypothesis that for death due to failure of the circulatory system among Scots there was a significant association between age at death and whether death occurred in Scotland or abroad.

RESULTS

Of the 572 deaths reported between 2000 and 2004, 73% occurred in the European region and 10% in the Americas. With respect to the cause, trauma accounted for 20.4%, infectious diseases 1.5%, and other non-infectious causes accounted for 75.5% of deaths. Among the latter, the major cause of death was due to failure of the circulatory system (77.0%). A significant association was observed between death abroad due to failure of the circulatory system and younger age at death for all (χ(2) = 26.9, df = 3, p < 0.001) and for males (χ(2) = 20.7, df = 3, p < 0.001) but not for females (χ(2) = 2.7, df = 1, p = 0.099).

CONCLUSIONS

The data indicates a low rate of death among Scots traveling abroad, with trauma and other non-infectious causes being the most common cause of death; failure of the circulatory system was the most common cause of death in the latter group. Europe and the Americas were the most common locations of death. Although travel health services should continue to advise travelers to developing countries on infectious disease risks, it is also important that travel health acts as venue for providing key advice and preventative means to all travelers, including those to developed countries. Those agencies, organizations, and companies who deal with travelers along their journey should also engage with travel health experts and practitioners to reduce the risk of adverse outcomes, including death, to travelers.

Travel medicine research priorities: establishing an evidence base

BACKGROUND

Travel medicine is the medical subspecialty which promotes healthy and safe travel. Numerous studies have been published that provide evidence for the practice of travel medicine, but gaps exist.

METHODS

The Research Committee of the International Society of Travel Medicine (ISTM) established a Writing Group which reviewed the existing evidence base and identified an initial list of research priorities through an interactive process that included e-mails, phone calls, and smaller meetings. The list was presented to a broader group of travel medicine experts, then was presented and discussed at the Annual ISTM Meeting, and further revised by the Writing Group. Each research question was then subject to literature search to ensure that adequate research had not already been conducted.

RESULTS

Twenty-five research priorities were identified and categorized as intended to inform pre-travel encounters, safety during travel, and post-travel management.

CONCLUSION

We have described the research priorities that will help to expand the evidence base in travel medicine. This discussion of research priorities serves to highlight the commitment that the ISTM has in promoting quality travel-related research.

Knowledge, attitudes, and practices of business travelers regarding influenza and the use of antiviral medication

BACKGROUND

This study aimed to determine the knowledge, attitudes, and practices of Swiss business travelers with regard to influenza and the use of antiviral medication.

METHODS

Questionnaires, available in three languages, were distributed manually and online through companies, organizations, and travel medicine specialists in Switzerland to business travelers who were traveling during the period January 2005 to April 2009.

RESULT

In total, 661 questionnaires were fully completed and evaluated. A total of 58.9% (n = 388) of the respondents stated that they had contracted influenza in the past; some 48.6% (n = 321) of the travelers had been vaccinated against seasonal influenza at least once in their lifetime; 87.1% (n = 576) of the travelers knew that influenza can be transmitted by droplets; and 62.3% (n = 412) were aware of transmission by direct contact. Almost all respondents (96.8%; n = 633) recognized fever as a main symptom of influenza, 80.0% (n = 523) knew about muscular aches and pain, 79.5% (n = 520) about shivering, and 72.9% (n = 477) about joint pain. Some 38.0% (n = 250) of the respondents stated that the annual vaccination is their preferred prevention method for influenza, 35.6% (n = 234) would neither do an annual vaccination nor carry antiviral medication, 16.0% (n = 105) would carry antiviral medication, 8.5% (n = 56) would prefer to do both the annual vaccination and to carry antivirals, and 2.0% (n = 13) would use antivirals as influenza prophylaxis. Regarding prevention, the majority (78.9%; n = 498) of the travelers did not seek advice on influenza before going on their last business trip, 58.0% (n = 381) did not take any preventive measures against influenza, 27.2% (n = 179) had their annual vaccination, and 15.7% (n = 103) observed hand hygiene. Of the travelers, 9.7% (n = 64) carried antiviral medication on their last business trip and 7.0% (n = 46) actually used this medication.

CONCLUSIONS

Business travelers have a good knowledge about the transmission and the symptoms of influenza but guidelines are needed that concisely address the indications for influenza vaccination in travelers and the carriage and use of antiviral medication.

Knowledge, attitudes, and practices of US travelers to Asia regarding seasonal influenza and H5N1 avian influenza prevention measures

BACKGROUND

International travel is a potential risk factor for the spread of influenza. In the United States, approximately 5%-20% of the population develops an influenza-like illness annually. The purpose of this study was to describe the knowledge, attitude, and practices of US travelers to Asia regarding seasonal influenza and H5N1 avian influenza (AI) prevention measures.

METHODS

We surveyed travelers to Asia waiting at the departure lounges of 38 selected flights at four international airports in New York, Chicago, Los Angeles, and San Francisco. Of the 1,301 travelers who completed the pre-travel survey, 337 also completed a post-travel survey. Univariate and multivariate logistic regression were used to calculate prevalence odds ratios (with 95% CI) to compare foreign-born (FB) to US-born travelers for various levels of knowledge and behaviors.

RESULTS

Although the majority of participants were aware of influenza prevention measures, only 41% reported receiving the influenza vaccine during the previous season. Forty-three percent of participants reported seeking at least one type of pre-travel health advice, which was significantly higher among US-born, Caucasians, traveling for purposes other than visiting friends and relatives, travelers who received the influenza vaccine during the previous season, and those traveling with a companion. Our study also showed that Asians, FB travelers, and those working in occupations other than health care/animal care were less likely to recognize H5N1 AI transmission risk factors.

CONCLUSION

The basic public health messages for preventing influenza appear to be well understood, but the uptake of influenza vaccine was low. Clinicians should ensure that all patients receive influenza vaccine prior to travel. Tailored communication messages should be developed to motivate Asians, FB travelers, those visiting friends and relatives, and those traveling alone to seek pre-travel health advice as well as to orient them with H5N1 AI risk factors.

Clinical and epidemiological characteristics of imported infectious diseases in Spanish travelers

INTRODUCTION

Spain could be a potential area in Europe for the development and spread of emerging diseases from the tropics due to its geoclimatic characteristics, but there is little information on infectious diseases imported by travelers. The aim of this article was to analyze clinical-epidemiological characteristics of infectious diseases imported by Spanish travelers from the tropics.

METHODS

A retrospective descriptive study of 2,982 travelers seeking medical advice who return ill from the tropics was conducted. Demographic data, details of travel (destination, type, and duration), preventive measures, clinical syndromes, and diagnoses were analyzed.

RESULTS

Nearly half (46.5%) the travelers had traveled to sub-Saharan Africa; 46.5% reported a stay exceeding 1 month (and almost a quarter more than 6 months). Following pre-travel advice, 69.1% received at least one vaccine and 35.5% took malarial chemoprophylaxis with variations according to geographical area of travel. In all, 58.8% of this took chemoprophylaxis correctly. Most common syndromes were fever 1,028 (34.5%), diarrhea 872 (29.3%), and cutaneous syndrome 684 (22.9%). Most frequent diagnoses were traveler's diarrhea (17.2%), malaria (17%), and intestinal parasites (10.4%). The three main syndromes in travelers to the Caribbean-Central America, Indian subcontinent-Southeast Asia, and other areas were diarrhea, fever, and cutaneous syndrome (p < 0.05); in sub-Saharan Africa were fever, cutaneous syndrome, and diarrhea (p < 0.05); and in South America were cutaneous syndrome, diarrhea, and fever (p < 0.05). Travelers to sub-Saharan Africa showed a higher frequency of malaria, rickettsiosis, filariasis, and schistosomiasis (p < 0.05); those to South America showed cutaneous larva migrants, other ectoparasitosis, and cutaneous/mucocutaneous leishmaniasis; and those to the Indian subcontinent-Southeast Asia showed intestinal parasitosis, arboviriasis, and enteric fever (p < 0.05).

CONCLUSIONS

Increased international travel is a key factor for the development and spread of emerging pathogens. Information on these diseases is essential to establish early warning mechanisms and action plans. Spain represents a unique setting for this.

Self-reported symptoms of infection among travelers departing from Sydney and Bangkok airports

BACKGROUND

Data on the burden of illness in travelers departing from both developing and developed countries within the Asia-Pacific region is scarce. We conducted a survey to assess symptoms of infection among travelers within the region.

METHODS

A self-administered questionnaire was distributed to travelers departing Sydney airport, Australia, for destinations in Asia and departing Bangkok Airport, Thailand, for Australian destinations during the respective winter months of 2007. A two-stage cluster sampling technique was developed to ensure representativeness and a weighting was applied to the Sydney sample. Travelers were assessed for symptoms of infection (fever, sore throat, diarrhea, rash, and myalgia), travel activities, and social contact in the 2 weeks prior to departure.

RESULTS

A total of 843 surveys was included in the final sample (Sydney 729, response rate 56%; Bangkok 114, response rate 60%). Overall, 45.6% of respondents were Australian residents and 26.7% were residents of countries in Asia. At least one symptom of infection was reported by 23.8% of respondents and 5.4% reported two or more symptoms of infection in the 2 weeks prior to departure. The proportion reporting symptoms was higher in those departing Bangkok compared to Sydney. Significant risk factors for the reporting of symptoms differed between residents and visitors departing each study site. Activities resulting in high rates of social contact prior to travel, particularly contact with febrile persons, were found to be independent predictors of reported symptoms.

CONCLUSIONS

Self-reported symptoms of infection were common in our sample of travelers. Infectious diseases in travelers can result in spread across international borders and may be associated with the frequency of social contacts and reported illness among travelers.

Travelers as a sentinel population: use of sentinel networks to inform pretravel and posttravel evaluation

The establishment of collaborative sentinel surveillance networks specifically to monitor disease trends among travelers offers new options for evaluating travel health issues. These networks can inform pre- and posttravel patient management by providing complementary surveillance information, facilitating communication and collaboration between participating network sites, and enabling new analytical options for travel-related research. The two major multinational sentinel networks are TropNetEurop and GeoSentinel. Practical examples demonstrating their significant contributions to improved travel health information are discussed. Data obtained from studying health problems among travelers may also have significant benefits for local populations in resource-limited countries. However, there are limitations of data collected by sentinel networks, so they should be considered as complementary tools and not relied on as an exclusive basis for evaluating health risks among travelers.

Health risks and travel preparation among foreign visitors and expatriates during the 2008 Beijing Olympic and Paralympic Games

During the 2008 Olympic and Paralympic Games, we conducted surveillance of illnesses among travelers at six Beijing clinics. Surveys asked about demographic, pre-travel, and vaccination information, and physician-provided diagnoses. Of 807 respondents, 38% and 57% were classified as foreign visitors (FV) and expatriates, respectively. Less than one-half of FV sought pre-travel advice; sources included health-care providers and friends/family. FV vaccination rate was also low; however, most vaccines given were recommended by the Centers for Disease Control and Prevention. The most common FV diagnoses were respiratory, injury/musculoskeletal, and gastrointestinal illnesses; for expatriates, injury/musculoskeletal, respiratory, and dermatologic were the most common illnesses. Respiratory illnesses in expatriates were significantly less in 2008 than during 2004-2007 (chi(2) = 10.2; P = 0.0014), suggesting that control programs may have reduced pollutants/respiratory irritants during the 2008 Games. We found no previous studies of health outcomes among expatriates living in cities with mass travel events. These findings highlight the need to continuously disseminate information to health-care providers advising travelers.

24 Longaandoeningen

Longproblemen tijdens of na een verblijf in de tropen kunnen acuut (zoals Legionella-pneumonie) of chronisch van aard zijn (longtuberculose). Reizigers die longklachten hebben, zullen meestal eerst naar de huisarts gaan. Deze kan verwijzen naar een internist of longarts, een kliniek met expertise in tropische ziekten of (voor onderzoek op tuberculose) een GGD in Nederland, of een VRGT-polikliniek in Vlaanderen.

Defining infections in international travellers through the GeoSentinel surveillance network

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