Travel‐Related Morbidity in Children: A Prospective Observational Study

Suzanne F. van Rijn MB, Gertjan Driessen MD, David Overbosch MD, PhD, Perry J.J. van Genderen MD, PhD
DOI: 144-149 First published online: 1 May 2012


Objective Scarce data are available on the occurrence of ailments and diseases in children during travel. We studied the characteristics and frequencies of ailments in children aged 0 to 18 years and their parents during traveling.

Methods A prospective observational study on ailments reported by children and parents traveling to (sub)tropical countries was conducted. The ailments were semi‐quantitatively graded as mild, moderate, or severe; ailments were expressed as ailment rates per personmonth of travel.

Results A total of 152 children and 47 parents kept track of their ailments for a total of 497 and 154 weeks, respectively. The children reported a mean ailment rate of 7.0 (5.6–8.4) ailments per personmonth of travel; 17.4% of the ailments were graded as moderate and 1.4% as severe. The parents reported a mean ailment rate of 4.4 (3.1–5.7); 10.8% of the ailments were graded as moderate and 5.5% as severe. Skin problems like insect bites, sunburn and itch, and abdominal complaints like diarrhea were frequently reported ailments in both children and parents. Children in the age category 12 to 18 years showed a significantly higher ailment rate of 11.2 (6.8–14.1) than their parents.

Conclusions Skin problems and abdominal problems like diarrhea are frequently reported ailments in children and their parents and show a high tendency to recur during travel. The majority of these ailments are mild but occasionally interfere with planned activities. Children in the age group 12 to 18 years are at a greater risk of developing ailments during a stay in a (sub)tropical country and they should be actively informed about the health risks of traveling to the tropics.

Increasingly, children travel with their parents to (sub)tropical destinations. The great variety of destinations and reasons for traveling illustrate that traveling to (sub)tropical countries has become common practice.1 Research shows that at least one third of the adults traveling to a (sub)tropical country becomes subjectively ill.2 In contrast, only scarce data are available on the prevalence of ailments in children traveling to (sub)tropical countries, while they have special needs and vulnerabilities and are believed to be more susceptible to diseases.3 The health risks of traveling to a (sub)tropical destination are not exactly known for children. Hagmann and colleagues retrospectively studied illnesses in children after international travel with and without pre‐travel advice. In their study, young children had higher proportionate morbidity rates.4 Newman‐Klee and colleagues stated that the similar incidence of morbidity in children and adults, as well as the mildness of the morbid episodes, challenges the view that it is unwise to travel with small children.5

We initiated a prospective study which aimed at (1) assessing the incidence rate of ailments in children and their parents or caregivers, further referred to as parents, traveling to (sub)tropical destinations, and (2) characterizing the types of ailments occurring and defining risk factors for traveling children in comparison to their parents.


This prospective observational study was conducted at the Travel Clinic of the Havenziekenhuis in Rotterdam, the Netherlands, from May to August 2010. Ethical clearance was granted by the ethics committee of the Erasmus Medical Centre, Rotterdam. Participants were included after written informed consent. Families visiting the Travel Clinic for pre‐travel health advice and expat families receiving a medical checkup were eligible for inclusion. The inability to read and write in Dutch was considered an exclusion criterion. All participants received a standardized questionnaire, detailing 33 defined ailments.6 The forms were filled out prior to departure and weekly during their stay abroad. A parent filled out the questionnaires of children with an age below 12 years. Participants who failed to return or complete their questionnaires were considered lost to follow‐up. Ailments were graded semi‐quantitatively as follows:

  • Grade I (mild): In cases where an ailment did not affect daily routine.

  • Grade II (moderate): In cases where an ailment interfered with planned activities.

  • Grade III (severe): In cases where an ailment necessitated a visit to a doctor or clinic.

The ailment rates were expressed as the number of ailments per personmonth of travel. Given the broad array of destinations, destinations were grouped by continent in Asia, Africa, and South and Central America (S/C America). Turkey was regarded as an Asian country. To evaluate ailments rate in relation to a specific destination, ailments were also grouped in dermatological disorders, respiratory disorders, diarrheal disorders, and systemic febrile illnesses.

Statistical analysis was performed with GraphPad Prism software, version 5.03 (GraphPad software, Inc., San Diego, CA, USA). The Log‐rank (Mantel–Cox) test was used for comparison of Kaplan–Meier survival curves. Ailment rates between the various age categories were compared with the Kruskal–Wallis (non‐parametric ANOVA) test followed by Dunn's multiple comparisons test. Relative risks were calculated using the Fisher's exact test using Yate's continuity correction.


Response Rate

Of the 233 children and 104 parents participating, we excluded 12 children and 7 parents who changed their travel plans, traveled to a European country, or traveled after September 2010, leaving 221 children and 97 parents. In total 152 children (69%) and 47 parents (48%) returned their questionnaires. The general characteristics and travel demographics are shown in Table 1. Asia and Africa were the most frequently visited continents. Thirteen children and three parents traveled to northern Africa; the remaining 21 children and 9 parents traveled to other African countries. The median duration of the stay abroad of all participants was 3 weeks, ranging from 1 to 9 weeks.

View this table:
Table 1

Characteristics of the study population and travel demographics

Duration of travel (wk)Destination
Age (y)Persons (n)Median (y)Male/FemaleTotalMedianRangeContinentn(%)
S/C America*15
S/C America210
S/C America1622
S/C America410
S/C America511
  • * S/C America denotes South and Central America.

Profile of Ailments Before Travel

Table 2 shows the pre‐existing morbidity in children and parents. Insect bites (occurring in 10.6% of the children), diarrhea (8.6%), and earache (7.9%) were the most reported ailments in children before travel, respectively. In parents, headache (occurring in 8.5% of parents), insect bites (4.3%), and common cold (2.1%) were frequently reported. Travel was associated with an almost threefold increase in risk of acquiring an ailment in children; a threefold increase in risk was noted for their parents.

View this table:
Table 2

Ailment profile of children and their parents before and during travel

Before travelDuring travelRelative risk
Ailment(n)(%)(n)(%)RR95% CI
Children with ailments
Insect bites1610.66140.43.82.3–6.3
Abdominal pain96.02617.22.91.4–6.0
Common cold96.02315.22.61.2–5.3
Any ailment5033.112884.82.62.0–3.2
Parents with ailments
Insect bites24.31736.28.52.1–34.8
Common cold12.1612.86.00.8–48.0
Abdominal pain00.0510.6n.a.
Sleeping disorder00.0510.6n.a.
Muscular pain12.–27.8
Any ailment1123.43472.33.11.8–5.3
  • n.a. = not available.

Profile of Ailments During Travel

Overall, children reported a mean ailment rate of 7.0 (95% confidence interval 5.6–8.4) ailments per personmonth travel. As shown in Tables 2 and 3, insect bites (comprising 17.4% of the ailments and 40.4% of the children) were the most frequently reported ailments among children, followed by fatigue (7.7% of the ailments and 26.5% of children) and diarrhea (7.6% of ailments and 29.8% of children). Even though insect bites dominated the ailment profile of children during travel, severe cases were only anecdotically reported; more than 99% of the insect bites resulted in mild symptoms of low impact.

View this table:
Table 3

Severity and recurrence rate of ailments in children and parents during travel

Severity of ailment
Grade IGrade IIGrade IIITotalAilment recurrence rate
Ailment(n*)(%)(n* )(%)(n* )(%)(n* )(%)(%)
Insect bites17296.652.810.617817.465.8
Abdominal pain3771.21426.911.9525.150.0
Common cold3986.549.124.4454.449.0
All ailments82981.117817.4151.51,022100.0
Insect bites50100.000.000.05026.066.0
Muscular pain890.419.600.094.763.9
Common cold675.0225.
Sleeping disorder7100.
Abdominal pain350.0116.7233.363.128.6
All ailments16183.72110.8105.5192100.0
  • * Expressed per personmonth of travel.

The ailment rate in parents was 4.4 (3.1–5.7) ailments per personmonth. The most reported ailments in parents were insect bites (26.0% of ailments; 36.2% of the parents), followed by diarrhea (13.0% of the ailments; 31.9% of the parents) and sunburn (5.7% of the ailments; 12.8% of the parents). In 9.1% of the ailments, diarrhea was graded as severe making diarrhea an ailment of substantial impact in adults.

As shown in Table 3, five children reported a total of nine grade III ailments. One child reported four grade III ailments (coughing, shortness of breath, common cold, and nausea). Another child reported two grade III ailments (fatigue and fever). The remaining three children each reported one grade III ailment (abdominal pain, fever, and insect bites, respectively). Four parents reported a total of nine grade III ailments. One of them reported four severe ailments (fever, nausea, diarrhea, and abdominal pain). One parent reported three severe ailments (nausea, diarrhea, and abdominal pain). Two parents reported one severe ailment each (earache and animal bite), respectively.

Insect Bites

Children reported 149 insect bites (corresponding with 178 insect bites in Table 3 when denominated per personmonth of travel), consisting of 100 (67%) mosquito bites, 5 (3.4%) horseflies, 1 (0.6%) beetle and 43 (29%) unspecified species. Parents reported 41 insect bites of which 26 were mosquito bites, 1 sand fly, and 14 unspecified species.

Ailments Within Families

Since families had comparable exposure to destination‐specific health risks, we also compared 47 child–parent pairs to find out whether both children and parents suffered similar ailments. The number of ailments of siblings was averaged in the event that a parent had more than one accompanying child. The data showed a significant correlation in number of ailments within families (rs = 0.71; p < 0.01). No significant correlation was observed in relation to severity.

Recurrence Rate

The 10 most recurring ailments in children and parents are shown in Table 3. Insect bites recurred the most in children, followed by itch and malaise. In parents, the most frequently recurring ailments were insect bites, followed by muscular pain and rash. Children reported insect bites to occur in 71% of the weeks, whereas parents reported insect bites in 61% of the weeks (data not shown).

Risk Factors for Ailments


Figure 1 shows the distribution of the four main ailment categories (diarrheal disorders, dermatologic disorders, respiratory disorders, and systemic febrile illnesses) per continent. Dermatological disorders were particularly prevalent in Asia and S/C America, whereas, compared to these continents, diarrheal disorders were more common in Africa (p < 0.0001).

Figure 1

Distribution of ailments in children in relation to continent of destination. Figures do not add up to 1,022 ailments because two children (four ailments) traveling to Australia are missing from this graph. *South and Central America. **Number of ailments reported per corresponding continent per personmonth of travel.

Age of participants

The parents remained asymptomatic for a longer period than children (p < 0.0001), as shown in Figure 2. After 1 week, 60% of the parents remained free from ailments in contrast to 40% of the children. Children in the age group 12 to 18 years reported a significantly higher ailment rate [11.2 (6.8–14.1) ailments per personmonth] than parents (p < 0.05).

Figure 2

Kaplan–Meier curve of the occurrence of ailments in children and their parents in relation to duration of travel. *A significant difference in “survival” (p < 0.05).


Our prospective observational cohort study showed that about 85% of all children and 70% of all parents reported some kind of ailment during travel. Around one sixth of the reported ailments were graded as moderate or severe, indicating some or substantial interference with planned activities. Overall, children reported more ailments compared to their parents, with the age group 12 to 18 years reporting the highest incidence rates of ailments of all age groups. However, the profile of these ailments was comparable to those observed in children in the other age groups. We hypothesize that the age group 12 to 18 years may be under less strict parental supervision as compared to the other age groups in children and may therefore employ more risk‐seeking behavior. This assumption has recently been validated by Han and colleagues, who showed an association between risk‐taking attitudes and youth travel behavior.7 However, we cannot exclude the possibility that the difference in number of reported ailments may partly be related to the finding that children of 12 to 18 years of age were allowed to self‐report their ailments, whereas the ailments in the other child age groups were reported by parents.

The ailment profile of both children and parents in our study was dominated by skin lesions, in particular insect bites. One could argue that insect bites do not represent a “true” ailment and that the high incidence of insect bites might have overshadowed the other findings. On the other hand, all participants in this study were free to report any ailment before or during travel. The high reported incidence rates of insect bites in both children and parents suggest that these insect bites led to some kind of discomfort. Indeed, in some children the occurrence of insect bites led to a visit to a doctor or hospital or to a change in itinerary. However, in the majority of cases in children and parents the ailments were rated as grade I, indicating no substantial impact on daily activities. It is certainly interesting to note that besides insect bites, itch and sunburn were frequently reported as well, even though advice on personal protective measures was given to these families prior to travel. The high incidence of skin problems, particularly those related to insect bites, might suggest a poor compliance with the use of insect repellents and sun blocking agents, but might also indicate a limited effectiveness of these measures under circumstances of intense exposure.

Consistent with other studies, diarrhea was also a frequently reported ailment in both children and parents. About one third of all travelers developed these ailments, despite pre‐travel health advice on food‐ and water‐borne risks and the ways to avoid these risks. In particular, abdominal problems, including diarrhea, appeared to hamper the travel‐related quality of life since almost 30% of these ailments were graded as moderate or severe, suggesting a major impact of these ailments on quality of life during travel.

In Asia and S/C America, skin problems appeared to be more prevalent than in Africa, whereas GI symptoms were more prevalent in Africa, suggesting a differential risk in acquiring ailments in relation to destination. This is only partially in line with the observation of others, but the generalization of our observations may be hampered by the limited sample size of travelers to a specific continent. In the study from Freedman and colleagues, acute diarrhea was seen disproportionately in persons traveling to south central Asia.8 Dermatologic disorders were seen disproportionately less commonly in persons traveling to sub‐Saharan Africa or south central Asia.8 Health professionals may use these observations to customize travel health advice depending on the risk profile of the travel destination. As might be anticipated, our data showed a significant correlation in number of ailments between children and their parents, probably representing comparable exposure to environmental and travel‐related health risks. In contrast, we did not observe clustering of severe ailments within families.

Newman‐Klee and colleagues examined illnesses in children traveling to the tropics and who received pre‐travel advice.5 They concluded that the similar incidence and mildness of morbid episodes challenges the view that it is unwise to travel with small children. Since most ailments reported were graded as mild and few visits to a doctor or hospital were needed, we agree with this statement. However, our data indicate that children between 12 and 18 years experience more ailments suggesting that this age group needs to be more actively informed about the health risks of traveling to (sub)tropical destinations.

It should be borne in mind that our study may have had several limitations. First, reporting ailments per week instead of per day may have introduced a recall and reporting bias, resulting in an underestimation of the incidence of ailments. Secondly, we only included children and parents who received pre‐travel health advice; as a consequence, the incidence rates of ailments may even be higher in children traveling without any form of pre‐travel health advice.


Skin problems and abdominal problems like diarrhea are frequently reported ailments in children and their parents and show a high tendency to recur during travel. The majority of these ailments are mild but occasionally interfere with planned activities. Children in the age group 12 to 18 years are at a greater risk of developing ailments during a stay in a (sub)tropical country and they should be actively informed about the health risks of traveling to the tropics.

Declaration of Interests

P.J.J. van Genderen received speaker's fee and reimbursement from GlaxoSmithKline and Sanofi Pasteur MSD for attending symposia. D.O. received speaker's fee and reimbursements from GlaxoSmithKline and Crucell and from GlaxoSmithKline for attending symposia.

The other authors state they have no conflicts of interest to declare.


This study was financially supported by an unconditional grant of the Port of Rotterdam. We thank all health professionals at the Travel Clinic in Rotterdam for their co‐operation and Henk Koene for his helpful assistance with data management.


  • Presented at the 23rd Havensymposium in Rotterdam on 26 November 2010.


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