Tiger mosquitoes in Nîmes: a case of dengue fever identified in the city center, an investigation in progress

This Wednesday 15 and Thursday 16 June, the presence of tiger mosquitoes in the arena sector will be closely scrutinized before, if necessary, carrying out a mosquito control treatment. “The risk of contamination is quite low” according to the ARS.

An imported case of dengue has just been identified in Nîmes. As required by the procedure in such circumstances, the Regional Health Agency (ARS) conducted “an epidemiological investigation” with the patient. “The objective was to know, during the period of viremia (presence of virus in the blood, editor’s note), where the person went, for how long, and who they visited”, details the departmental delegate of the ARS Claude Rolls.

Possible nocturnal adulticide treatment

A step which triggered a second investigation, entomological this one, in progress this Wednesday and Thursday and carried out by the vector control operator Altopictus, mandated by the Regional Health Agency. This will intervene in the city center, in the immediate vicinity of the arenas, to search for the presence, or not, of the tiger mosquito (Aedes albopictus)vector of dengue fever.

If this investigation turns out to be positive, a nocturnal adulticide treatment will be planned for the area in the coming days. It will be carried out from a vehicle (pick-up type) and potentially completed by pedestrian treatment. The insecticide used (Aqua-K Othrine, based on deltamethrin to be precise) is authorized by the regulations. The Gard beekeepers’ union has already been informed of its possible use because it can threaten the survival of bees; even if in the present case, in the heart of the city, the impact in this area would undoubtedly be limited.

“Cutting the Chains of Transmission”

“We are confronted every year with imported cases of dengue, even if it remains quite rare, continues Claude Rols. Our job is to cut the chains of transmission as quickly as possible, that is why these investigations are carried out and that we accompany the people concerned. In this case, the risk of contamination is quite low.

In recent years, the Gard, Nîmes in particular, had experienced two small dengue “clusters”, in the hills and at the Mas de Ville, where there, about fifteen indigenous cases (with contamination on the spot, and not reported in Metropolitan France) had been registered. The scenario that the public authorities want to avoid.

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