For the first time, indigenous cases of “West Nile” fever “, transmitted by mosquitoes, were observed in Île-de-France, the health authorities announced on Wednesday August 13, while chikungunya households multiply in metropolitan France at a particularly high level. “” Two indigenous cases of infection by the Western Nile virus – West Nile Virus – were detected in people residing in Seine -Saint -Denis Summates the Regional Health Agency (ARS) in Île-de-France in a press release. “” These are the first identifications of local vector transmission of the West Nile virus in Île-de-France. »
This virus is transmitted via mosquito bites. But, unlike chikungunya or dengue, It is not the tiger mosquito that is involved, but the genus Culex, much more widespread in mainland France. Another difference with these two other diseases, “West Nile” fever is not transmitted from one human to another by the mosquito, but from an infected bird. In 80 % of cases, the infection is asymptomatic. When it is symptomatic, it manifests itself by a pseudo-grippal syndrome (large fever accompanied by headaches, muscle or abdominal pain, nausea, diarrhea). In less than 1% of cases, serious neurological complications (meningitis, encephalitis) may appearsometimes causing death. “” Generally, the patient spontaneously recovers, sometimes with sequelae. But viral infection can be fatal mainly in the elderly “Warns the ARS. She also indicated that she has implemented a certain number of measures, in collaboration with other health players, in order to limit the health risk: awareness of health establishments likely to accommodate contaminated people, epidemiological survey, mobilization of animal health actors to strengthen surveillance in birds
Aboriginal cases have already been reported in metropolitan France in previous years – around forty in 2024 – but never so in the north. This summer, apart from the two Ile-de-France cases, five other indigenous cases were recorded in the south, in Provence-Alpes-Côte-d’Azur, said the National Public Health Agency France in another report, published on Wednesday.
Reinforced monitoring of other arboviroses still in progress
The health agency also continues to follow the evolution of Aboriginal cases of Chikungunya in mainland France each week. They are this summer at a particularly high level this summer, after an epidemic in Reunion which facilitated the importation of the virus. From now on, ” 23 episodes of chikungunya totaling 115 cases (with) 1 to 23 cases per episode We were counted in mainland France, according to Public Health France, adding that six of these episodes are closed.
In terms of dengue, six households have been identified for a total of eleven cases. The previous week, the record rose to five homes for nine cases. The transmission of dengue and chikungunya in mainland France is a consequence of the establishment of the tiger mosquito. He was still absent from the metropolis a few decades ago, but he now settled there, against a background of global warming.