Two recent Aboriginal cases of “West Nile” in Seine-Saint-Denis, why is it notable?
Rachel Bellone: ”This situation is quite unprecedented because it is the first time that we have identified cases of” West Nile “fever in Île-de-France, in a fairly short period of time, of serious shape, and, for the season too, it is quite early”. Cases of “West Nile” have already been identified in France, but in previous years, it was mainly in the Southwest. It is quite worrying too because usually, the “West Nile” is a large asymptomatic disease. So basically, what we detect is a bit of the iceberg. We try to understand why there were these cases in Île-de-France because the region is a little outside the migratory traffic lane of birds that can wear the virus. ”
Mosquito -related diseases are transmitted more and earlier?
“In mid-August, there were more than 150 cases of local transmission of the dengue and chikungunya virus. The situation is quite unique this year; In 2024, we were just over 80 cases all over the summer season. The peak of local transmissions is generally between the month of August and the month of September […] With the return of travelers. This year, we have already reached almost the total of the previous season before we even spent this peak period. Also new, the first case of Chikungunya was detected in May. In previous years, it was generally not before June. Overall, in France, the situation is quite worrying because the number of cases and episodes increases each year. The first years, when we had the first detections, it was not necessarily recurrent. There, since 2022, each year, cases of local transmission have been detected, either dengue virus or chikungunya virus. We also had a small episode of transmission of the Zika virus in France. The homes are therefore more and more important and important. So it worries a little for the years to come. »»
Are the causes of this increase multifactorial?
“There is, of course, the presence of the tiger mosquito in the territory. The tiger mosquito arrived in 2004 in the south of France and, in 20 years, it colonized almost all of the territory. And there are epidemics all over the world: when people travel and return to the territory, they find the mosquito, a competent vector, all the conditions are met for a transmission. There is also, of course, the environment. Increasingly, we end up with a climate favorable to the proliferation of tiger mosquitoes and the transmission of these arboviruses. And there is an epidemic of chikungunya in Reunion, which increases the pressure of introduction of the virus. »»
Individually, how to avoid contamination?
“We can protect ourselves from bites. We can also eliminate everything that is larval cottages – the places where mosquitoes will reproduce -, everything that is stagnant water, typically flower pots. It’s very pretty in summer, but you have to eliminate them. It helps a lot to eliminate the risk of transmission. »»