Surge in imported dengue fever cases to France from overseas

There have been 500 cases of dengue fever reported in mainland France among people who have travelled to at-risk areas since May 1, and more than 2,000 cases since January, new figures show.

Of these 2,166 reported cases in 2024, the majority (82%) were contracted in the French overseas territories of Guadeloupe and Martinique, and 5% in French Guiana, said Santé publique France (SPF) in its latest update, published on June 11. 

Of the 500 detected since May 1, 63% were from these territories, where a dengue fever epidemic is currently spreading.

Of the 500 cases imported since May 1, 429 of those were in people who live in departments where tiger mosquitoes are present. 

Read also: Alarm over massive rise of mosquito-spread diseases caught in France

Tiger mosquitoes (Aedes albopictus) spread diseases including dengue fever by biting an infected person, and then biting another person, transmitting the disease in the blood. ‘Imported’ cases of dengue can, in this way, soon become ‘native’ cases, meaning they involve people who have not recently travelled to a normally at-risk country.

Dengue is not contagious between humans except via mosquito bites. Tiger mosquitoes have now been detected in all regions of France.

Read also: Tiger mosquitoes now in Normandy, last region of France to escape them 

The highest number of imported cases since May 1 were reported in people who live in: 

• Auvergne-Rhône-Alpes (82 cases)

• Provence-Alpes-Côte d'Azur (71 cases)

• Ile-de-France (61 cases, plus one case of chikungunya).

So far - up to June 11 - there have been no reports of ‘native’ cases.

Tiger mosquitoes were first detected in France in 2004, and have spread across the country due to rising temperatures and climate change.

Despite their ‘big cat’ name, they are smaller than ‘regular’ mosquitoes (less than 0.5cm in length). They are also silent, and tend to be more active during the day.

How to reduce tiger mosquito numbers

Health authority Anses gives the following tips to help avoid the insect:

• Regularly empty or remove any stagnant water, including from cups under flower pots, vases, etc., or fill them with sand in order to maintain humidity without stagnant water

• Store buckets, gardening equipment, toys, and other containers away from the rain

• Cover water collection containers with mosquito netting or fabric

• Clean gutters to allow proper drainage

Read also: Act now to limit tiger mosquitoes at French home this summer 
Read also: Tiger mosquitoes: How you can help stop their spread in France 

How can I protect myself from bites?

Health officials advise:

• Using repellents, including products that include Deet, IR 3535, KBR 3023, or citriodiol

• Wearing long clothing

• Hanging mosquito nets

Consult a doctor if you develop symptoms such as joint/muscle pain, headaches, a skin rash with or without fever, or conjunctivitis within 10 days of your return from an affected country, or after having been bitten in France.

It is also recommended that you report any sightings or bites to Signalement-moustique.anses.fr, the specialist government health department (Anses) website. The page also includes more information about the insect and how to prevent its spread.