Travel-related infections presenting in Europe: A 20-year analysis of EuroTravNet surveillance data

Abstract

Background: Disease epidemiology of (re-)emerging infectious diseases is changing rapidly, rendering surveillance of travel-associated illness important.

Methods: We evaluated travel-related illness encountered at EuroTravNet clinics, the European surveillance sub-network of GeoSentinel, between March 1, 1998 and March 31, 2018.

Findings: 103,739 ill travellers were evaluated, including 11,239 (10.8%) migrants, 89,620 (86.4%) patients seen post-travel, and 2,880 (2.8%) during and after travel. Despite increasing numbers of patient encounters over 20 years, the regions of exposure by year of clinic visits have remained stable. In 5-year increments, greater proportions of patients were migrants or visiting friends and relatives (VFR); business travel-associated illness remained stable; tourism-related illness decreased. Falciparum malaria was amongst the most-frequently diagnosed illnesses with 5,254 cases (5.1% of all patients) and the most-frequent cause of death (risk ratio versus all other illnesses 2.5:1). Animal exposures requiring rabies post-exposure prophylaxis increased from 0.7% (1998-2002) to 3.6% (2013-2018). The proportion of patients with seasonal influenza increased from zero in 1998-2002 to 0.9% in 2013-2018. There were 44 cases of viral haemorrhagic fever, most during the past five years. Arboviral infection numbers increased significantly as did the range of presenting arboviral diseases, dengue and chikungunya diagnoses increased by 2.6% and 1%, respectively.

Interpretation: Travel medicine must adapt to serve the changing profile of travellers, with an increase in migrants and persons visiting relatives and friends and the strong emergence of vector-borne diseases, with potential for further local transmission in Europe.

Funding: This project was supported by a cooperative agreement (U50CK00189) between the Centers for Disease Control and Prevention to the International Society of Travel Medicine (ISTM) and funding from the ISTM and the Public Health Agency of Canada.

Keywords: Eurotravnet; Geosentinel; Infectious diseases; Sentinel surveillance; travel.

Fig. 1

(A) Age and sex for ill travelers seen after or during travel n = 92,061 patients with age and sex known, 46,012 males and 46,049 females, 34 deaths. (B) Age and sex for ill travelers with migration travel only. N = 11,201 patients with age and sex known, 6737 males and 4473 females, 11 deaths.

Fig. 2

(A) Travel reason and clinical setting by year of clinic visit; n = 103,739 patients. (B) Region of exposure by year of clinic visit; n = 103,739 patients. (C) Top diagnoses in all patients by clinical setting by year of clinic visit; n = 127,772 diagnoses. Multiple entries per patient possible.

Fig. 3

Top 10 diagnoses by region of acquisition in travelers seen after travel.

Fig. 4.

(A) Malaria species by 5 years, shown by% of malaria diagnoses. (B) Origin of malaria as Plasmodium species per region of acquisition, shown by% of malaria diagnoses per region. (C) Origin of malaria as Plasmodium species per region of acquisition, shown as numbers of patients.