Increase in imported dengue cases in Spain in 2024: analysis by region of exposure and evolution since 2016

Abstract

Introduction: Dengue is a viral disease transmitted by Aedes mosquitoes. It is not endemic in Europe, and reported cases are mainly imported. The aim of this study is to describe in greater detail the cases imported into Spain in 2024 according to the place of exposure, in relation to those reported since 2016.

Method: Retrospective descriptive study of imported dengue cases reported to the National Epidemiological Surveillance Network (RENAVE) in 2024, according to place of exposure and their evolution since 2016. Sociodemographic variables, place of exposure, reason for stay abroad, hospital admission and death.

Results: Between 2016 and 2024, 3,451 imported dengue cases were reported, with a historic high in 2024 (1,113 cases; 32.3% of the total). In 2024, an atypical increase in cases was observed in January-April, in addition to the July-October peak of previous years. The Americas (73.0%) was the main region of exposure in 2024, and also in the months of January-April (86.0%), mainly Argentina and Paraguay. In 2024, family visits also predominated (52.8%) and no increase in hospitalisations was observed.

Discussion: The unprecedented increase in imported cases in 2024 reflects the transmission situation in endemic areas and the international mobility patterns of travellers from our country. These findings reinforce the need to strengthen epidemiological and entomological surveillance, as well as prevention strategies aimed at travellers and residents with family ties in endemic areas, especially in areas where Aedes albopictus is present, due to the risk of autochthonous outbreaks.