It’s an unusual number, and it’s growing. According to the latest report from Public Health France (SPF) dated this Friday, September 16, 41 cases of autochthonous dengue fever and 5 outbreaks have in total been reported in mainland France since the beginning of the year. People with this infectious disease, which is transmitted from person to person through the bite of an infected tiger mosquito, have not traveled to an area where the virus usually circulates in the 15 days preceding the onset of symptoms, according to the definition of the Ministry of Health.
On Wednesday, the health authorities had announced 26 cases, identified in the Provence-Alpes-Côte d’Azur and Occitanie regions, had specified the General Directorate of Health (DGS). The most important focus is located in the Alpes-Maritimes, in the neighboring towns of Saint-Jeannet, Gattières and La Gaude: 26 cases have been counted, with symptoms which started between August 1 and September 6, said this Friday Marie-Claire Paty, director of infectious diseases at Public Health France.
The balance sheet will probably be revised upwards in the coming days and weeks. If the peak of cases is in August and September, “there have been episodes in the past in September-October, so we could have new ones and we are not out of the risk period”, noted Marie-Claire-Paty.
“We are going towards an extension and a multiplication of episodes”
The level of cases identified is already higher than that observed in previous years. Since 2010, SPF has recorded barely more than ten indigenous cases in its heaviest annual reports. In 2020, the health authorities had identified 14 cases of autochthonous dengue fever spread over six outbreaks, and in 2021, two cases.
“We are moving towards an extension and a multiplication of these episodes” of dengue fever in metropolitan France, underlined Marie-Claire Paty. To explain the increase in the number of cases, she mentioned “the extension of the tiger mosquito on French territory”, and more generally, its global extension, while it has been monitored since the end of the 1990s. Preview for the first time in Menton (Alpes-Maritimes) in 2004, the tiger mosquito or mosquito Aedes albopictus which can also transmit chikungunya and zika, then gradually moved up to the north of the country and it is now permanently present in 2022 in 67 departments. The virus circulates regularly in the French departments of the Antilles, as well as in the French islands of the Pacific and the Indian Ocean.
Map of metropolitan departments where the presence of the tiger mosquito is known on January 1, 2022.
Ministry of Health
Deforestation and urbanization also play a role in its proliferation, as well as climate change which contributes to its development, with factors such as “hot temperatures, precipitation, floods but also droughts”, specified SPF, while the current weather conditions are favorable to their multiplication. “The movements of people and travelers contribute to the spread of these diseases”, added Marie-Claire Paty.
Flu-like symptoms
The symptoms of dengue fever are most often flu-like (fever, headache, body aches) and appear within 3 to 14 days after the mosquito bite. Most often benign, dengue can however take hemorrhagic forms. Treatment is symptomatic, including pain and fever. “The prevention of bites and the fight against the proliferation of mosquitoes are essential to limit the occurrence of epidemic outbreaks,” insists the Ministry of Health.
In particular, he recalls the importance of storing anything that may contain water, sheltering from the rain, wearing loose-fitting and covering clothing, using a skin repellent, or even, if necessary, mosquito nets. on openings (doors and windows).
The ministry also reiterates the need to immediately consult your doctor in the presence of suggestive symptoms (high fever of sudden onset, muscle or joint pain, eye pain, fatigue, headache), in particular if a diagnosis of Covid-19 has ruled out and if they appear within fifteen days of returning from a trip to the tropics. At the same time, mosquito control operations are set up by the regional health authorities as soon as an imported case or a local case is reported.