Ana Vázquez González
Senior Scientist at the Health Institute Carlos III
Dengue is one of the vector-borne diseases whose incidence has increased most rapidly in recent decades, with an estimated 100-400 million infections each year, approximately 80 % of which are mild and/or asymptomatic. It is currently distributed in large tropical and subtropical areas throughout the world, mainly in urban and semi-urban regions, affecting more than 120 countries, with the Americas, South-East Asia and the Western Pacific being most affected by the disease.
In addition to the burden of disease produced in regions where the virus is present, dengue represents a public health risk in non-endemic territories where Aedes mosquitoes (which act as a vector transmitter) are present, as is the case in Spain, where Ae. albopictus has been established since 2004 and is expanding. In Europe, dengue virus caused major epidemics in the last century until the end of the 1920s, with Ae. aegypti being the vector involved, but after its eradication, all cases described have been imported cases in travellers from endemic areas. However, since 2010, cases of autochthonously transmitted dengue have been described in different European countries, most of them associated with the presence of Ae. albopictus, such as Croatia, France, Portugal (Madeira, an outbreak of more than 2000 cases associated with Ae. aegypti), Germany and Italy. In Spain, the first cases were reported in 2018 and 2019. Travel restrictions in 2020 favoured the non-emergence of new cases.
The news of the detection in Germany of two autochthonous cases of dengue (one confirmed and one probable) in travellers from Ibiza, an island where Ae. albopictus has been present since 2014, reaffirms the need for surveillance of the disease in the months of peak vector circulation in all areas where Ae. albopictus is present. Early detection of imported cases is key to the control of the disease as it facilitates the implementation of prevention measures, being important in this aspect the establishment of vector control (elimination of breeding sites, fumigation...) and personal protection against bites (repellents, mosquito nets...).