thematic dossier
Vector-borne diseases
Les maladies à transmission vectorielle sont des maladies infectieuses transmises par des vecteurs, essentiellement insectes et acariens hématophages. Santé publique France participe à leur...
Chikungunya, dengue, Zika: 2021 figures
Arboviral diseases are viral illnesses caused by arboviruses transmitted by vectors such as mosquitoes or ticks to animal or human hosts. Each year, Santé publique France coordinates the surveillance of arboviral diseases—including dengue, chikungunya, and Zika—and today is releasing the figures for 2021.
Dengue, Zika, and chikungunya are three arboviral diseases—viral illnesses transmitted by mosquitoes of the Aedes genus. They are subject to enhanced seasonal surveillance from June 1 to November 30 each year in France, a period during which activity of the Aedes albopictus mosquito is expected in the departments where the vector is present.
Santé publique France, as a key player in the fight against arboviruses, coordinates this surveillance and publishes weekly national seasonal surveillance data between June and November. Specific regional reports are also published in regions where the mosquito is present. A summary is then produced at the end of the year and made available on our website.
What does the surveillance of arboviruses—dengue, chikungunya, and Zika—entail?
The presence of arboviruses in France
The mosquito that transmits arboviruses, Aedes albopictus (also known as the tiger mosquito), is established in several French regions and has been spreading across the entire country since 2004. Thus, in France, epidemiological surveillance of arboviruses is part of a strategy for prevention and the implementation of vector control measures in all departments where the vector is present.
The objectives of arbovirus surveillance
The goal of surveillance is to enable rapid intervention by vector control services around potentially viremic cases in areas where the vector is present, in order to prevent a local transmission cycle.
Mandatory reporting of arbovirus cases
To detect transmission risks, surveillance relies on mandatory reporting of all biologically confirmed cases, whether imported or locally acquired. Each report is submitted by physicians and laboratories and triggers an immediate epidemiological and entomological investigation.
Chikungunya, dengue, Zika: 2021 key figures and results
From May 1, 2021, to December 10, 2021, the following were confirmed in mainland France:
164 imported cases of dengue, including 105 from Réunion; 144 cases were diagnosed in departments with documented establishment of Aedes albopictus.
3 imported cases of chikungunya
0 imported cases of Zika
Focus on locally transmitted dengue cases identified in 2021
One locally transmitted case of dengue was identified in the Var department on July 26, 2021. No other cases were identified, including during door-to-door surveys conducted on August 2 and 9.
Another locally transmitted case of dengue was identified in Montpellier on November 5, 2021. Vector control measures were carried out around the patient’s home on November 11 and 15. No other cases have been identified, including during door-to-door surveys conducted on November 22 and 23, 2021.
Compared to the 2020 season, the number of imported cases, particularly of dengue, was much lower this year: 909 cases of dengue in 2020 (consolidated data) versus 164 in 2021. This lower activity is attributable to the absence of epidemic circulation of dengue in the French departments of the Americas during the 2021 enhanced seasonal surveillance period. For the record, more than 80% of imported dengue cases in 2020 were returning from a stay in Martinique or Guadeloupe.
Number of confirmed imported cases of chikungunya, dengue, and Zika, by region, in metropolitan France and in departments with documented presence of Aedes albopictus (May 1, 2021, to December 10, 2021)
| Regions | Total Metropolitan France | Departments with documented presence of Aedes albopictus | ||||||
|---|---|---|---|---|---|---|---|---|
| Dengue | Chikungunya | Zika | Flavivirus | Dengue | Chikungunya | Zika | Flavivirus | |
| Auvergne-Rhône-Alpes | 20 | 0 | 0 | 0 | 20 | 0 | 0 | 0 |
| Burgundy-Franche-Comté | 5 | 0 | 0 | 0 | 4 | 0 | 0 | 0 |
| Brittany | 3 | 0 | 0 | 0 | - | - | - | - |
| Centre-Val-de-Loire | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Corsica | 2 | 0 | 0 | 0 | 2 | 0 | 0 | 0 |
| Grand-Est | 6 | 0 | 0 | 0 | 4 | 0 | 0 | 0 |
| Hauts-de-France | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Ile-de-France | 47 | 1 | 0 | 0 | 44 | 1 | 0 | 0 |
| Normandy | 7 | 0 | 0 | 0 | - | - | - | - |
| New Aquitaine | 21 | 1 | 0 | 0 | 21 | 1 | 0 | 0 |
| Occitanie | 24 | 0 | 0 | 0 | 24 | 0 | 0 | 0 |
| Pays-de-la-Loire | 7 | 0 | 0 | 0 | 6 | 0 | 0 | 0 |
| Provence-Alpes-Côte d'Azur | 19 | 1 | 0 | 0 | 19 | 1 | 0 | 0 |
| Total | 164 | 3 | 0 | 0 | 144 | 3 | 0 | 0 |
The Role of Santé publique France in the Surveillance and Prevention of Arboviral Diseases
As the surveillance coordinator, Santé publique France, in collaboration with other partners—Regional Health Agencies and National Reference Centers—is responsible for:
Defining, steering, and coordinating epidemiological surveillance in France
Adapting surveillance to regional specificities and risks
Studying prevention behaviors regarding arboviral diseases in metropolitan France to identify levers for action to improve vector control
Contributing to the provision of information and raising awareness among healthcare professionals, local authorities, and the general public regarding these diseases and preventive measures
