Profile of Travel‐Associated Illness in Children, Zürich, Switzerland

Thomas Hunziker MD, Christoph Berger MD, Georg Staubli MD, Alois Tschopp PhD, Rainer Weber MD, David Nadal MD, Christoph Hatz MD, Patricia Schlagenhauf PhD
DOI: http://dx.doi.org/10.1111/j.1708-8305.2012.00611.x 158-162 First published online: 1 May 2012

Abstract

Background The number of families traveling with their children to their country of origin and/or to tropical destinations has increased in Switzerland and includes a changing profile and multinational range of patients. Defining the profile of reported travel‐associated illnesses will help to improve the prevention and treatment of such illnesses in children.

Methods This study includes children aged up to 16 years who sought medical advice for a presumed travel‐related illness at the emergency room of the University of Zürich Children's Hospital during the period July 2007 to December 2008.

Results We analyzed data on 328 children (58.8% male, mean age: 4.62 y) who presented with travel‐associated illness. Our analysis included 155 traditional (mainly tourist) travelers, 162 children who were visiting friends and relatives (VFR), and 11 immigrants. Some 11% were hospitalized. No deaths occurred. The main conditions recorded were diarrheal illness (39%), respiratory (28.7%) and febrile/systemic illness (13.4%). With increasing age, the proportion of children with diarrheal disease increased, while the proportion with respiratory illness declined. There were significant associations between geographic area of exposure and the profile of travel‐related disease (p < 0.001). Among 36 children with more serious diseases requiring hospitalization, 12 (3.7% overall) presented with potentially serious diseases: malaria (n = 2), Salmonella typhi (n = 3), Salmonella paratyphi (n = 2), meningococcal meningitis (n = 1), tuberculosis (n = 2), visceral leishmania (n = 1), and hepatitis A (n = 1). Eleven of the 12 children presenting with these potentially serious illnesses were VFR or immigrant children.

Conclusion The main diagnoses for ill‐returned Zürich children who presented for emergency care were diarrhea, respiratory, and febrile/systemic illness. A broad spectrum of morbidity was seen including meningococcal meningitis, malaria, tuberculosis, typhoid fever, leishmania, and hepatitis A. Diagnoses varied between geographic regions visited, and VFR child travelers constituted a large proportion of sick‐returned children presenting for emergency care.

Approximately 21% of Switzerland's 7.7 million population are less than 20 years of age, and 22% of Swiss residents are foreign‐born.

International travel has become increasingly popular worldwide. The number of families traveling with their children to and from tropical destinations has steadily increased over the last years providing potential exposures to tropical diseases. This is a global trend. Travel data of US residents from 2000 reported that 7% (1.9 million) of US international travelers were children.1 There is little published literature on the incidence and type of illness in Europe‐based children who travel.

The aims of this study are to characterize the profile of travel‐associated illness occurring in children in Zürich, identify risk groups, and use this information as an evidence base to formulate pre‐travel health advice.

Methods

The Zürich Centre of the GeoSentinel surveillance network (GeoSentinel, The Global Surveillance Network of the International Society of Travel Medicine and the Centers for Diseases Control and Prevention; http://www.geosentinel.org) provided clinician‐based pediatric surveillance data for this analysis during an 18‐month period. The Zürich site is a composite site of the University Hospital and the University of Zürich Children's Hospital. For the purpose of our study, patients were included if they were younger than 16 years and had sought medical advice for a presumed travel‐related illness at the Emergency Room of the University of Zürich Children's Hospital, Switzerland, between July 2007 and December 2008. Final diagnoses were assigned by a physician.

Data were collected according to a standardized, anonymous questionnaire and entered into a Structured Query Language database. The questionnaire comprises demographic data (age, sex, country of birth, country of residence, current citizenship), travel history in the last 5 years, inpatient or outpatient status, major clinical complaint (more than one per patient is possible), reason for most recent travel, and patient classification. Final diagnoses were assigned a diagnostic code from a standardized list of >500 diagnoses, which were also categorized into 21 broad syndrome groups.

Definitions

Patient diagnoses were defined as follows: “diarrhea” included gastroenteritis, acute diarrhea of parasitic, viral, bacterial or unknown origin, and chronic diarrhea of unknown origin; “dermatologic”; “febrile/systemic illness”; “other gastrointestinal and genitourinary” included abdominal pain, hepatitis, pyelonephritis, appendicitis, and urinary tract infection; “injury and musculoskeletal” included trauma, fracture, arthritis, nonspecific symptoms or findings, and vertigo; “ophthalmologic”; “oral and dental”; and “respiratory” included upper and lower respiratory infections, otitis, bronchitis, and asthma.

Due to small case numbers, a simplified regional classification was used: Asia (North East Asia, South Central Asia, South East Asia), South and Central America (Central America, South America), North America, Australia/New Zealand, Caribbean, Eastern Europe, Western Europe, Middle East, North Africa, sub‐Saharan Africa.

Children were divided into three age‐groups with approximately equal numbers of cases: “infant” between 1 and 23 months of age, “preschool child” from 2 to 5 years of age, and “child and adolescent” from 6 to 16 years of age.

Statistics

The software program Statistics Package for the Social Sciences (SPSS) version 17 was used for descriptive statistical analysis. Statistical significance variables were achieved by using chi‐square test.

Results

In the period between July 2007 and December 2008, a total of 40,486 emergency consultations were documented at the University of Zürich Children's Hospital. We analyzed 328 children included in the GeoSentinel database. The age range was 0 to 16 years with a mean age of 4.62; 58.8% were male and 89% were outpatients. Two thirds of inpatients (total 11% inpatients) were male. The patients presented during the calendar year with peak numbers following school vacation periods. The basic demographic pattern is shown in Table 1.

View this table:
Table 1

Demographic characteristics of ill travelers presenting during and after travel at the University of Zürich Children's Hospital

Total: 328 (100%)Male: 193 (58.8%)Female: 135 (41.2%)
Mean age (y)4.624.884.25
 Age 0 to <2 y103 (31.4%)61 (31.6%)42 (31.1%)
 Age 2 to ≤5 y113 (34.5%)62 (32.1%)51 (37.8%)
 Age 6 to 16 y112 (34.1%)70 (36.31%)42 (31.1%)
Reason for travel
 VFR162 (49.4%)98 (50.8%)64 (47.4%)
 Tourism155 (47.3%)89 (46.1%)66 (48.9%)
 Immigration11 (3.4%)6 (3.1%)5 (3.7%)
Clinical setting
 Seen after travel273 (83.2%)162 (83.9%)111 (82.8%)
 Seen during travel44 (13.4%)25 (13.0%)19 (8.1%)
 Immigration travel only11 (3.4%)6 (3.1%)5 (3.7%)
Patient type
 Inpatient36 (11%)25 (13.0%)11 (8.1%)
 Outpatient292 (89%)168 (87.0%)124 (91.9%)
Citizenship
 Switzerland142 (43.3%)85 (44.0%)57 (42.2%)
 Western Europe41 (12.5%)23 (11.9%)18 (13.3%)
 Eastern Europe89 (27.1%)57 (29.5%)32 (23.7%)
 Asia + Middle East34 (10.4%)17 (8.8%)17 (12.6%)
 Other22 (6.7%)11 (5.7%)11 (8.1%)
  • VFR, visiting friends and relatives.

Our analysis included 155 tourist travelers, 162 visiting friends and relatives (VFR) travelers, and 11 children who were traveling for the purpose of immigration. Table 2 shows the disease spectrum by gender and age‐groups. Leading diagnosis groups were diarrhea (39%), respiratory (28.7%), and febrile/systemic illness (13.4%).

View this table:
Table 2

Travel‐related diagnoses in ill children presenting to the emergency room at the University of Zürich Children's Hospital stratified by age, sex, and reason for travel

Male: 193 (58.8%)Female: 135 (41.2%)Tourism: 155 (47.3%)VFR: 162 (49.4%)Age 0 to <2 y: 103 (31.4%)Age 2 to ≤5 y: 113 (34.5%)Age 6 to 16 y: 112 (34.1%)
Diarrhea* 128 (39%)77 (39.9%)51 (37.8%)61 (39.4%)66 (40.7%)34 (33.0%)44 (38.9%)50 (44.6%)
Febrile/systemic illness 44 (13.4%)22 (11.4%)22 (16.3%)20 (12.9%)23 (14.2%)15 (14.6%)14 (12.4%)15 (13.4%)
Respiratory* 94 (28.7%)54 (28.0%)40 (29.6%)43 (27.7%)44 (27.2%)41 (39.8%)31 (27.4%)22 (19.6%)
Dermatologic 27 (8.2%)14 (7.3%)13 (9.6%)13 (8.4%)12 (7.4%)4 (3.9%)14 (12.4%)9 (8.0%)
Other gastrointestinal and genitourinary 16 (4.9%)10 (5.2%)6 (4.4%)9 (5.8%)7 (4.3%)3 (2.9%)4 (3.5%)9 (8.0%)
Oral and dental 10 (3.0%)8 (4.1%)2 (1.5%)4 (2.6%)6 (3.7%)4 (3.9%)4 (3.5%)2 (1.8%)
Injury and musculoskeletal 6 (1.8%)5 (2.6%)1 (0.7%)4 (2.6%)2 (1.2%)0 (0%)1 (0.9%)5 (4.5%)
Ophthalmologic 3 (0.9%)3 (1.6%)0 (0%)1 (0.6%)2 (1.2%)2 (1.9%)1 (0.9%)0 (0%)
  • * This table shows a change in illness pattern by age with an increase in diarrheal illness and a decline in respiratory illness by age.

With increasing age, the proportion of children with diarrheal disease increased, while the proportion with respiratory illness declined (Table 2). There were significant associations between geographic area of exposure and the profile of travel‐related disease (p < 0.001) (Table 3). Among travelers returning from Western Balkan Countries and North Africa, diarrhea was the leading diagnosis. In Asia and America (South, Central, and North), respiratory illness is the most frequent diagnosis, and in sub‐Saharan Africa, febrile/systemic illness was most frequently reported (Table 3).

View this table:
Table 3

Regions and diagnoses with highest number of cases

Diarrhea (%)Respiratory (%)Febrile/systemic illness (%)Other (%)Total
Western Europe31.929.215.323.672
Eastern Europe40.927.36.425.5110
Asia33.333.318.714.775
North Africa72.713.64.59.122
Sub‐Saharan Africa28.614.357.1014
Latin America483601625
Other304030010

Only a few patients presented with potential serious diseases: two patients with the diagnosis of malaria (both acquired in the sub‐Saharan region), three patients with Salmonella typhi diagnosis (1 Middle East and 2 Asia), and two with Salmonella paratyphi diagnosis (2 Middle East). Also, a patient from the sub‐Saharan zone was diagnosed with meningococcal meningitis. Two cases of tuberculosis, one visceral leishmania and one hepatitis A completed the spectrum of exotic diseases. All of these children were hospitalized (Table 4) representing one third of ill‐returned hospitalized children. Nine of 12 children presenting with potential serious diseases were VFR, 2 of them were immigrants, and 1 tourist traveler. Thus, the overall frequency of more severe, potentially life‐threatening diseases among this population of ill‐returned children was 5.5% among those VFR, 18% among immigrants, and 0.6% among tourist travelers.

View this table:
Table 4

Potentially serious diagnoses with sex, age, travel reason, and exposure country

Meningitis, meningococcalMale age 4, inpatientImmigration from Chad
Salmonella typhiFemale age 3, inpatientVFR travel to Bangladesh
Salmonella typhiMale age 6, inpatientVFR travel to Iraq
Salmonella typhiFemale age 5, inpatientImmigration from Manila
Salmonella paratyphiFemale age 1, inpatientTourism in Turkey
Salmonella paratyphiMale age 11, inpatientVFR travel to Turkey
Malaria Plasmodium falciparumMale age 1, inpatientVFR travel to Ghana
Malaria P falciparumMale age 2, inpatientVFR travel to Ghana
Leishmania, visceralFemale age 1, inpatientVFR travel to Portugal
TuberculosisMale age 2, inpatientVFR travel to Kosovo
TuberculosisFemale age 6, inpatientVFR travel to Turkey
Hepatitis AMale age 13, inpatientVFR travel to Kosovo
  • VFR, visiting friends and relatives.

Discussion

This study shows that returned children, who are sick enough to go to the emergency room, present with a broad spectrum of travel‐associated morbidities, mainly diarrheal illness (39%), respiratory (28.7%), and febrile/systemic illness (13.4%). Some 12 (3.6%) of children presenting with travel‐associated illness have potential serious diseases requiring hospitalization. Eleven of the 12 children presenting with serious illness were VFR or immigrant children.

Our study has certain limitations; patients included in the study do not necessarily represent the whole population of Zürich. Many ill‐returned children will visit pediatricians or general practitioners, and some children will present in the emergency room due to an inadequate access to the primary health care system. Furthermore, the number of travelers returning in good health is also unknown. Therefore, incidence rates or relative risks cannot be estimated. Similarly, patients with mild or self‐limiting disease are more likely to see a general practitioner. On the other hand, Zürich is a large city with a mixed sociocultural population, and many of these patients may prefer to go to a more anonymous University Children's Hospital, particularly if they do not have a regular general practitioner.2

Only 0.8% (328 of 40,486) of all emergency consultations had a travel‐related reason. Nevertheless, the travel history is essential in ascertaining the possible cause of disease and in the selection of the appropriate diagnosis. Recently, a global analysis of ill‐returned children showed that diarrhea is the leading diagnosis in returned children, and our study confirms this finding.1 The fore‐mentioned global analysis, however, shows significant dermatological proportional morbidity that was not observed in the Zürich collective. Our analysis is thus particularly valuable for physicians and pediatricians in the Central European setting. Another report shows no significant difference in the incidence of morbid episodes between children and adults, except for fever which is diagnosed more frequently in children.3

The study confirms that many of the diagnosed illnesses post travel are commonplace and of short duration. Travelers' diarrhea affects over 50% of travelers and can disrupt holidays.4 The most frequent bacterial pathogens of travelers' diarrhea are Escherichia coli, Campylobacter, Shigella, and Salmonella.3–6

As diarrhea was the most frequent illness in children in this study, this theme is important for inclusion in the pre‐travel consultation. Parents should be prepared to treat mild diarrhea with oral rehydration and additionally loperamide for older children.7,8

In this study, two malaria cases were found, both from Ghana in VFR travelers. As a priority, malaria should be ruled out in children with febrile illness returning from malaria endemic areas. The pre‐travel advice is an ideal opportunity to provide concise malaria prevention guidelines and chemoprophylaxis for children.9 Mosquito bite protection is an essential component of malaria prevention, and N,N‐diethyl‐3‐methybenzamide (DEET) repellents can be used for infants aged >2 months.10 Generally, pediatric malaria case numbers are increasing as more children travel and the profile of migration is changing.11–13 In the study from Stäger et al.,14 returning to the country of origin to visit friends and relatives was a significant risk factor for the acquisition of malaria. A recent analysis suggests that it is cost‐effective to subsidize malaria chemoprophylaxis for low‐income travelers visiting high‐risk malaria endemic areas, and this may encourage use of malaria prophylaxis in VFR travelers.15 School‐, sport‐, and community‐based strategies to reach VFR children need to be evaluated.16

A relation between the place of exposure and the spectrum of disease can help in diagnostic approaches and empiric therapies.17,18 Nontravel medicine practitioners should be reminded to ask the question “did you travel recently?” when taking a history. Depending on the travel destination, travelers may be exposed to a number of infectious diseases; exposure depends on the presence of infectious agents in the respective area. The risk of becoming infected will vary according to the purpose of the trip, the itinerary within the area, the standards of accommodation, hygiene, and sanitation, as well as the behavior of the traveler and the reason for travel—whether it is for tourism, VFR travel, or for immigration.19

VFR travelers are exposed to an increased risk of travel‐related health problems.20–22 General practitioners should be aware of possibly serious travel‐related disease in VFR risk groups in their community. VFR travel to Africa is associated with malaria, while VFR travel to Asia including Turkey is associated with typhoid fever. Two cases of tuberculosis in VFR children were acquired in Turkey and Kosovo.

Conclusions

Physicians attending to returned ill children need to be aware of and to diagnose a complete range of diseases from commonplace to serious. Parents can be provided with a simple range of pediatric medications and instructions on how to treat self‐limiting conditions. The pre‐travel consultation is an opportunity to provide concise preventive advice for pediatric travelers. The country of origin of settled migrants has an important role to play in the diagnosis profile. VFR children will present with potentially more serious illnesses such as typhoid fever, hepatitis A, and malaria.

Declaration of Interests

P. S. has received research grants and consultancy fees from F. Hoffmann La Roche, speaker's honorary from GSK, and is an advisory board member of sigma tau. The other authors state that they have no conflicts of interest to declare.

Authors' Contributions Statement

All authors have seen and approved the final version of the paper. T. H. was involved in the concept, design, analysis, and writing/revising the paper. He is the guarantor. C. B. was involved with the concept and revision of the paper and gave major input and critical feedback. G. S. was key in capturing data on children presenting with travel‐related illness. A. T. provided significant statistical input. G. S., A. T., R. W., D. N., and C. H. critically revised the paper. P. S. was involved in the concept, design, analysis, and writing/revising the paper and she is the project supervisor.

Acknowledgments

We thank the members of the secretariat especially Mrs Lopez from the University of Zürich Children's Hospital, Division of Infectious Diseases.

References

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