The number of ailments of siblings find more 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. 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). Figure 1 shows the distribution of the four main ailment categories (diarrheal disorders, dermatologic CHIR-99021 chemical structure 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). 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). 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 enough 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.