Relative distribution of reported illness presentations among ill international travellers: a systematic review and meta-analysis

Background Travel-related illness challenges clinical care and public health surveillance. Gastrointestinal, febrile/systemic, and respiratory presentations contribute substantially to morbidity, but their subgroup-specific distribution, which may help align clinical and public-health priorities with traveller profiles, has not been quantitatively synthesised. We aimed to describe the relative distribution of reported illness presentations across major syndrome/system categories among ill international travellers. Methods We conducted a systematic review and meta-analysis of studies published between 2000 and 2025. Epidemiological studies reporting illness acquired during or following international travel were included. For each syndrome/system category (e.g., gastrointestinal, febrile/systemic), we estimated the pooled proportion using the IVhet model, with subgroup analyses by travel purpose (tourism, visiting friends and relatives [VFR], and business), destination income group (non-high-income vs high-income destinations), and age group. Results 80 articles met the inclusion criteria. Among tourists, gastrointestinal illness was the most frequent (42.7%; 95% CI 22.3–57.8), followed by dermatological/bite-related (30.7%; 95% CI 12.8–45.6) and febrile/systemic illness (25.4%; 95% CI 9.1–39.9). Among business travellers, gastrointestinal illness (53.8%; 95% CI 34.5–64.3) accounted for the largest pooled proportion, followed by febrile/systemic illness (34.4%; 95% CI 18.2–45.9). Among VFR travellers, febrile/systemic was most frequent (64.5%; 95% CI 38.1–72.9). Among travellers to non-high-income destinations, gastrointestinal (37.9%; 95% CI 23.8–47.4) and febrile/systemic (34.4%; 95% CI 20.9–43.9) illnesses were the most frequent; and among travellers to high-income destinations, respiratory (36.5%; 95% CI 18.6–49.4) and dermatological/bite-related (32.0%; 95% CI 15.1–44.8) illnesses were most frequent. Conclusions The pooled estimates describe the relative distribution of illness presentations represented in the included evidence. Subgroup-specific patterns may provide context for pre-travel counselling, post-travel assessment, diagnostic prioritisation, and syndromic surveillance but should not be interpreted as static or universally applicable proportions or as absolute risks among all travellers.