Introduction
The health authorities in England and France have reported a significant increase in local transmission clusters of the dengue virus in the Provence-Alpes-Côte d’Azur region since 2022. This rise in cases highlights the growing presence of arboviruses, including dengue, Chikungunya, and West Nile virus, in France. Public Health France emphasizes the importance of reporting these cases to limit transmission and advises on protective measures against mosquito bites.
Understanding Dengue
Dengue is an arbovirus transmitted to humans by Aedes mosquitoes. While 75% of cases are asymptomatic, the virus can cause severe symptoms and, in rare instances, lead to death. Originally endemic to tropical regions, dengue was introduced to Europe by infected travelers. The changing climate has allowed the Aedes albopictus species, commonly known as the tiger mosquito, to establish itself in mainland France since 2004.
Case Study: A Severe Dengue Infection
A 44-year-old woman, previously healthy, presented to emergency services in the UK with a high fever exceeding 40°C for three days, despite taking antipyretics. Her condition rapidly worsened, with symptoms including retro-orbital and muscular pain, and a maculopapular rash covering her body. She also experienced extreme fatigue, confining her to bed. Upon examination, there were no respiratory or cardiac issues, nor signs of meningitis. However, she had recently vacationed in the Alpes-Maritimes in August 2022, where family members exhibited similar symptoms.
Dengue infection was quickly suspected and confirmed through serological and molecular tests (RT-PCR). As her risk of severe disease was low, she was discharged and recovered swiftly at home.
Local Transmission Clusters
Between June and October 2022, the regional health agency reported three local transmission clusters of dengue in Fayence (7 cases), Saint-Jeannet and Gattières (34 cases), and Saint-Laurent-du-Var (10 cases). That year, local cases outnumbered those imported from endemic regions. Since then, arbovirus cases have been increasing across Europe and France.
In 2024, one local dengue case was reported in Occitanie, and two in the PACA region. Additionally, one Chikungunya case was reported in Île-de-France, and three local West Nile virus infections in PACA.
Health Authorities’ Recommendations
Health authorities stress the importance of promptly confirming suspected cases through testing and reporting them to the regional health agency (ARS). They also remind patients of protective measures against mosquito bites and the elimination of breeding sites, such as saucers and other containers that can hold stagnant water near homes.
New Vaccination Guidelines
The 2025 vaccination schedule has been updated to include the QDENGA vaccine in French territories in the Americas, Mayotte, and Réunion for:
– Children aged 6 to 16 who have previously had a dengue infection.
– Adults aged 17 to 60 with comorbidities, regardless of previous infection history.
This article was initially published on Univadis.fr, a member of the Medscape network, and was supplemented by Aude Lecrubier.
Source: [Medscape](https://francais.medscape.com/s/voirarticle/3612831)