‘Native’ case of dengue fever in Hérault, first in France in 2024

A case of ‘native’ dengue fever has been confirmed in the south of France - meaning the person became infected in France and not a high-risk area abroad - in the first such reported case of 2024.

Dengue fever is spread by tiger mosquitoes when they bite an infected person and then bite someone else. Tiger mosquitoes have become more prevalent in France over recent years amid rising temperatures and climate change, since first being reported in the country in 2004.

They are now in every region of France.

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

The native case of dengue was reported on July 8 in the department of Hérault, confirmed the Agence Régionale de Santé (ARS) in Occitanie. 

In a statement, the ARS said: “The ill person is being taken care of and their health condition is not worrying.”

It added that the nearby communes of Montpellier and Pérols were taking preventative action in a bid to stop the virus from spreading locally.

Read also: Latest on tiger mosquitoes in France: where, what risk and what to do 

This includes anti-mosquito spraying operations, as well as efforts to "eliminate larval breeding sites and adult mosquitoes in the places where the sick person lives and has been". 

A local survey will help to "identify any other people who may be ill", the ARS said.

Departments on alert

This is the first ‘native’ case of dengue to be reported in 2024. In 2023, around 50 native cases were reported, after a record of 66 in 2022.

The majority (90%) of France is now on ‘heightened vigilance’ for tiger mosquitoes, and 12 departments are on ‘maximum alert’ (purple, in a five-colour alert scale from green to yellow, to orange to red, and purple, from the website Vigilance moustiques).

They are: Val-de-Marne, Drôme, Alpes-Maritimes, Bouches-du-Rhône, Gard, Hérault Pyrénées-Orientales (plus the overseas departments of Mayotte, Réunion, Guyane, Martinique, and Guadeloupe).

This maximum alert level is for areas in which “one or several cases of native illnesses were recorded in 2023”, authorities said. 

Tiger mosquitoes can also spread cases of Zika and chikungunya, although cases of these are much rarer.

‘Unprecedented’ spike in cases

A spike in non-native cases - those picked up from a normally at-risk country - has also been recorded in France, linked to epidemics in the French overseas territories in the Caribbean, and a similar situation in the Americas.

Read also: Dengue fever cases surge in France since start of year 
Read also: Record number of dengue fever cases reported in France 

Authorities have called the current situation “unprecedented”, and have advised “heightened vigilance” ahead of an influx of people to France for the Olympic Games, which begin on July 26.

The best way to prevent the spread of the tiger mosquito is to get rid of standing and stagnant water, and you can prevent bites by using typical anti-mosquito methods, including wearing long clothing, spraying repellents, using mosquito nets, and burning citronella candles or similar.