Septic shock and severe acute kidney injury caused by West Nile virus in southern France

West Nile virus (WNV) is a neurotropic orthoflavivirus primarily transmitted by Culex mosquitoes and, rarely, through blood transfusion or organ transplantation. Birds constitute the main reservoir, while humans and horses are considered dead-end hosts.1 In 2025, 1,112 locally acquired WNV cases were reported across 14 European countries, including 62 in France, 31% of which occurred in the Bouches-du-Rhône department in southern France.2