Epidemiological update - dengue in Réunion

Epidemiological update

Since the beginning of 2018 and as of 14 May, 2 980 autochthonous cases of dengue have been reported in Réunion [1]. The main areas affected are in the western part of the island. The most prevalent serotype among dengue cases is DENV-2 and the main vector implicated in the outbreak is Aedes albopictus.

The current outbreak is significant as the number of cases exceeds the annual number of cases reported since 2010. The reasons for the sudden increase in 2018 are not well understood, but multiple factors occurring concurrently might have played a role in the development of this epidemic [2]. Further transmission can be expected until the beginning of the austral winter (between July and September). Control activities are currently in place and include active vector control, enhanced surveillance, blood safety measures and social mobilisation. 

The assessment of the transmission risk in the EU/EEA, as stated in ECDC’s Rapid Risk Assessment published on 16 April 2018, remains valid. The risk for onward transmission of dengue fever in Europe is linked to importation of the virus by viraemic travellers into receptive areas with established and active competent vectors (i.e. Aedes albopictus in mainland Europe, mainly around the Mediterranean sea, and Aedes aegypti on the island of Madeira [3]). Environmental conditions in Europe are now favourable for the growth of mosquito populations and will probably lead to a high vector abundance by early summer.  

Prior to this period of high vector abundance, there is a low likelihood of sustained autochthonous dengue virus transmission in continental Europe associated with introduction by a returning traveller from Réunion or other areas in the world with active dengue virus transmission. 



  1. Cire Océan Indien. Santé publique France. Surveillance de la dengue à la Réunion. Point épidémiologique au 14 Mai 2018. Saint Denis, La Réunion.2018 [cited 17 May 2018].  
  2. European Centre for Disease Prevention and Control. Dengue outbreak in Réunion, France - 16 April 2018. Stockholm: ECDC, 2018.
  3. European Centre for Disease Prevention and Control and European Food Safety Authority. Mosquito maps Stockholm: ECDC; 2018.