The diseases transmitted by mosquitoes spread a little more in France. This time, it is the Western Nile fever (or «West Nile»): Aboriginal cases-that is to say contracted in mainland France-were detected for the first time in Ile-de-France, announced this Wednesday, August 13, public health France. They were identified in two people in Seine-Saint-Denis.
Infection, one of the most widespread among the diseases transmitted by mosquitoes, is generally without symptoms. In approximately a fifth of the cases, it gives rise to a influenza state, with the brutal appearance of fever, headache, joint and muscle pain, or even a rash. The patient generally recovers spontaneously. In less than 1 % of cases, serious complications may however appear, until there is death.
Unlike chikungunya or dengue, it is not the tiger mosquito that transmits this virus by its bites, but the genus Culex, much more widespread in mainland France. Another difference with these two other diseases: fever «West Nile» is not transmitted from one human to another by the mosquito, but from an infected bird.
Aboriginal cases have already been reported in France in previous years – around forty in 2024 – but never so 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.
At the same time, chikungunya households are increasing in mainland France at a particularly high level, 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” have been recorded in France, says Public Health France in its weekly bulletin. Six of these episodes are closed. The previous week, the results were 16 households for 63 cases, an already record level. Regarding dengue, six households were identified for a total of eleven cases.
The transmission in France of these last two diseases is a consequence of the implantation 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.
