A second indigenous case reported in the Loire

On July 1, an adult, living in Saint-Chamond (Loire), presented symptoms evocative of dengue. As a reminder, this pathology, transmitted by the bite by a mosquito of the genus Aedes, manifests itself by a influenza state (fever, headache, aches, nausea, adenopathy) the 3 to 14 days following the bite. Three days later, his case was reported to the Regional Health Agency (ARS) Auvergne-Rhône-Alpes. The latter is said to be indigenous because the infected person contracted the disease on the national territory and did not trace in the contaminated zone within 15 days preceding the appearance of symptoms. Subsequently, an investigation was carried out and preventive measures were implemented to limit the risks of transmission.

“It is not possible to establish a link with the 1st Aboriginal case identified” in Saint-Chamond

This July 21, the ARS alerted to a second indigenous case in Saint-Chamond. The report was received on July 15. “At this stage, it is not possible to establish a link with the 1st Aboriginal case identified” in the town. “Investigations are still underway.” In the Auvergne-Rhône-Alpes region, between May 1 (start of reinforced surveillance) and July 15, 2025, 92 cases of imported dengue were recorded, including 8 in the Loire.

In order to prevent tiger mosquitoes in the vicinity from transmitting the disease to other people, the health authorities have implemented actions, such as an entomological and epidemiological survey as well as a demoustication operation on the night of July 21 to 22. “The inhabitants of the sectors concerned were informed by a flyer deposited in their mailbox. A hundred houses are affected. (…) The objective is to ensure that people living in the sector have not been contaminated by a tiger mosquito bite, to make them aware of the symptoms of dengue and to indicate the conduct to be followed in the event of symptoms.”

Dengue: How to avoid getting sick?

Adults returning from travel to tropical zone must be particularly vigilant. In detail, they should avoid being bitten by tiger mosquitoes upon their return and immediately consult a doctor if symptoms appear. Those living in a sector where tiger mosquitoes are present must also remain attentive and consult a practitioner in case of doubt. “As a reminder, dengue is a compulsory declaration disease: healthcare professionals must report to ARS any diagnosis of dengue.”