“The Spread of Dangerous Tiger Mosquitoes in Île-de-France Raises Public Health Concerns”

As elsewhere, as summer approaches, Ile-de-France residents fear mosquito bites. Particularly Aedes albopictusthis tiger mosquito, recognizable by its characteristic black stripes. The female of this species is subject to special monitoring for her ability to carry dangerous tropical viruses. In 2022, Île-de-France was placed in Red alert due to the presence of this small insect of 5 mm, according to the latest report from the Ministry of Health. A renewed level of surveillance for this year 2023, according to the site Vigilance-moustiques.com.

The “established and active” tiger mosquito in Île-de-France

The maps are formal: Paris, Hauts-de-Seine, Seine-Saint-Denis and Val-de-Marne are scarlet. Concretely, the tiger mosquito is there “established and active”. And this since the end of the 2010s. Nevertheless, in 2022, these insects proliferate less in Île-de-France than in the southern half of France. In the Ile-de-France region, less than 40% of the population lives in colonized municipalities, according to the Ministry of Health.

A “dengue” summer in 2022 in Paris

Even so, the tiger mosquito remains a public health problem, insofar as it can potentially be a carrier of a serious disease. Because the female Aedes albopictus is never dangerous except insofar as it has previously bitten an “infected” person. What remains a priori “excessively rare” in Île-de-France, especially for tropical afflictions, as noted the prefecture of the region in 2021.

But this situation could change. Last summer, Public Health France noted that between May 1, 2022 and October 26, 2022, Île-de-France displayed the highest number from cas d’arboviruses [maladies virales transmises par un arthropode (type moustique), ndlr] of metropolitan France. Among them, 71 cas confirmed/probable cases of dengue fever and eight confirmed cases of chikungunya were identified in an epidemiological report carried out on the territory.

The risk of autochthonous arbovirus

Still according to Public Health France, these cases have all were imported [Amérique latine / Caraïbes (41 %), Asie (32 %), Afrique (24 %) et Océan Indien (3 %)]. Among all the arboviruses, 65 (82%) were potentially viraemic [diffusion du virus dans le sang, ndlr].

This means that these conditions were potentially transmissible to others through the tiger mosquito, which feeds on the blood of its prey during the day. 20% of “contaminated” residents lived in municipalities colonized by the insect.

We are talking d’arbovirose autochtone when a person contracts a viral disease from a mosquito, without having traveled before. This was not the case in Île-de-France over the period, while 65 cas natives were counted in France on October 16, 2022. The largest number ever recorded.

Anticipate the Paris 2024 Olympic Games

In an opinion issued on Wednesday April 5, 2023, the Committee for monitoring and anticipating health risks (Covars) estimated that France could precisely experience outbreaks of dengue fever, Zika and chikungunya “over the coming summers”.

For the committee, this rise in power seems to be taking shape with regard to the combined action of the climate change (better survival of female mosquitoes) and increasing travel (circulation accrue des virus).

So much so that the committee advises anticipating “dengue fever cases during the 2024 Olympic and Paralympic Games”. And recommends simulating the occurrence of five sources of contamination around five JOP sites.

A relatively dazzling health escalation when no tiger mosquito was yet established in Île-de-France until 2015, the year when this species was considered active in the Val-de-Marne. Its territory then extended to Hauts-de-Seine in 2017, then to Paris and Seine-Saint-Denis in 2018.

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