Key Points

West Nile

• In late July 2023, locally acquired human cases were reported for the first time in the Nouvelle-Aquitaine region. As of September 26, 2023, 20 confirmed or probable locally acquired human cases had been identified (with symptoms beginning between mid-July and late August): 17 in Gironde and 3 in Charente-Maritime. Investigations are underway for 6 other individuals. In addition, 12 equine cases have been reported (8 in Gironde and 4 in Charente-Maritime) and 6 avian cases (Charente-Maritime). These cases indicate active circulation of the West Nile virus in Gironde and Charente-Maritime.

Usutu

• In France, the virus has been circulating since 2015, and until 2022, only two human cases had been detected: the first in Occitanie in late 2016 (in Hérault) and the second in Nouvelle-Aquitaine in the fall of 2022 (a case involving a person who had stayed in the Landes and Gironde departments). In early August 2023, two human cases of Usutu virus infection were identified in the region by the National Reference Center for Arboviruses. As of September 26, 2023, six locally acquired human cases—including four residents of Gironde, one in the Landes, and one in Charente-Maritime—had been identified. In addition, two avian cases were reported in Charente-Maritime and Haute-Vienne. The Usutu virus is therefore actively circulating in Gironde, Charente-Maritime, Haute-Vienne, and the Landes.

Chikungunya, dengue, Zika

• From May 1 to September 22, 2023, 89 imported cases of dengue and 4 imported cases of chikungunya were identified in the region (compared to 30 imported cases of dengue and 3 imported cases of chikungunya from May 1 to November 30, 2022). To limit the emergence of local transmission chains, 143 entomological surveys (mosquito searches) and 98 vector control treatments were carried out around cases residing in or passing through the region.