Europe has recorded its highest number of West Nile virus cases in three years, with Italy accounting for more than 80% of all confirmed infections.
As of August 28, a total of 430 cases had been reported across eight EU countries, including 27 deaths, according to the European Centre for Disease Prevention and Control (ECDC).
Experts warn that cases are expected to continue rising, with peak transmission likely between late August and September. The virus is primarily transmitted to humans through mosquito bites, and while most infections are asymptomatic, severe neuroinvasive forms have been reported, particularly among elderly individuals in Italy.
Italy Faces Widespread Infections and Deaths
The Italian Institute of Health (ISS) confirmed that the virus remains active in endemic areas in the country’s north and center. Of the 430 reported cases, 193 have developed into neuroinvasive disease. The regions most affected are Lazio, which includes Rome, with 62 cases and 11 deaths, and Campania, which has recorded 64 severe cases and 11 deaths.
West Nile virus has now been detected in 57 provinces across 15 Italian regions. The most recent fatality was a 92-year-old woman who died at Maggiore Hospital in Novara after being hospitalized in early August. Containment measures are being reinforced nationwide, especially among high-risk populations over the age of 80.
Health Authorities Expand Surveillance and Warnings
Since being declared endemic in Italy in 2008, the virus has been monitored through an extraordinary surveillance plan. This includes monitoring equines, sedentary bird species, and mosquito populations, especially those from the Culex genus, which are known vectors. According to the Italian Society of Equine Veterinarians, veterinarians are being encouraged to report suspected infections in horses.
In addition to West Nile virus, Italy has also reported other mosquito-borne illnesses in 2025, including 134 dengue cases (mostly travel-related), 102 chikungunya cases, 4 Zika virus cases, and 30 cases of transmissible traumatic encephalopathy. The majority of these infections have not resulted in fatalities.
Spain and Other Regions Report Low Activity
Unlike Italy, Spain has reported a quiet season for West Nile virus so far in 2025. Only five cases have been confirmed in the Extremadura region, two of which remain hospitalized. An additional equine case has been reported in Mahón, Menorca, marking the first known infection in that location.
In past years, Spain has experienced severe outbreaks, including 138 confirmed cases and 15 deaths in 2024. However, improved mosquito control campaigns and natural virus cycles have likely contributed to the reduced circulation observed this year.
The ECDC warns that the spread of West Nile virus and similar mosquito-borne diseases is becoming more prolonged, intense and geographically widespread. “Europe is entering a new phase, where more prolonged, widespread, and intense transmission of mosquito-borne diseases is becoming the new normal,” the agency stated.
As no specific treatment exists for West Nile virus, health authorities stress preventive measures such as the use of repellents, wearing light-colored clothing, and eliminating standing water to reduce mosquito breeding. Transmission risk typically declines with cooler weather in autumn.
