Reacción a "Reactions to the cases of autochthonous dengue fever detected in Ibiza in German tourists"

After many years of absence, dengue has re-emerged in the European region both through sporadic cases of local transmission, driven by the introduction of people infected with the virus, and through the invasion of the mosquito vector species Aedes aegypti and Aedes albopictus. The 2012 outbreak in Madeira, in addition to the impact on the health of the local population, health services and the economy, revealed how difficult it can be to control the circulation of pathogenic arboviruses, especially as Europe is already partially colonised by the dipteran vector Aedes albopictus, introduced in Mediterranean countries. While it is true that dengue transmission models suggest a low risk in Europe, these models rarely include A. albopictus transmission. 

During the dengue outbreak in Madeira, appropriate mosquito control measures were effectively implemented. The effectiveness of these measures, in terms of reducing the number of breeding sites, application of pesticides and insecticides, and public health education, largely worked. With no prophylactic vaccine or targeted therapies available, vector control remains the best alternative to restrict virus circulation. In fact, many European countries have already implemented surveillance and control measures for invasive mosquitoes, although only a few include dengue surveillance. 

Ongoing surveillance is essential. The surveillance initiated in Catalonia in 2015 to monitor imported cases and detect possible local transmission of arboviruses assessed the importance of entomological surveillance around viremic travellers, which may be effective for early detection of dengue virus in mosquitoes and therefore able to help prevent possible autochthonous transmission. 

Considering the increasing frequency of dengue epidemics worldwide and the movement of viremic hosts, new cases are expected to occur in Europe in the future, such as the one detected in France in 2022, with 65 autochthonous cases, six of which occurred in departments that had never experienced autochthonous dengue transmission, or the current one in 2023, detected in Ibiza, Spain, widely reported in the press. 

All the prerequisites for autochthonous dengue virus transmission - vectors, returning viremic travellers and climatic conditions - are present in Europe. The establishment of vector populations in peri-urban environments links humans and viruses, opening up the possibility of unexpected outbreaks. More cases are certain to occur and as long as no specific dengue prophylaxis or treatment is available, integrated vector management is the most sustainable control option.