Dengue - the underestimated risk in travellers.

In recent decades, the incidence, distribution and clinical severity of dengue have increased dramatically in most tropical and subtropical areas worldwide. As a consequence, and due to the expanding international tourism, health care providers in European travel clinics are more and more confronted with dengue, reflecting its global impact. Based on data of the European Network on Imported Infectious Disease Surveillance (TropNetEurop) and the German Surveillance Network on Imported Infectious Diseases (SIMPID), a total of 483 confirmed and probable cases of dengue fever, including 13 cases of dengue haemorrhagic fever were reported to the networks’ coordination centre between January 1999 and December 2002. There was a wide range of epidemiological and clinical features. Non-European travellers (immigrants or foreign visitors) were at 4.3-times higher risk of developing dengue haemorrhagic fever compared to European travellers. Infections were acquired in all endemic regions of the world, with highest frequencies in South-East Asian countries. Persons travelling to areas where dengue is endemic should avoid exposure to mosquitoes, and health care providers should consider dengue as a differential diagnosis in febrile travellers returning from the tropics after discounting malaria. Surveillance of imported dengue is crucial to monitor the risk of infection for travellers and to strengthen clinical awareness of the disease.