As of September 2026, European health authorities report a total of 979 human cases and 79 deaths driven by an intense circulation of the West Nile virus across Greece, Italia, Macedonia del Norte, and Países Bajos. Driven by rising temperatures, the vector-borne disease has already surpassed the entirety of infections recorded during the previous year.
In Plain English: The Clinical Takeaway
- Vector-Borne Transmission: The West Nile virus is transmitted primarily through the bite of infected mosquitoes, which thrive in warmer climates intensified by global heating trends.
- Neuroinvasive Risk: While many infections remain asymptomatic or present as mild febrile illness, a significant subset progress to neuroinvasive disease, the most severe form of the illness.
- Vulnerable Demographics: Older adults, particularly those of advanced age such as the reported average of 84 years in Greece, face the highest risk of severe complications and mortality.
Epidemiological Dynamics and National Tolls
According to updates published this September, seasonal transmission across Europe has accelerated sharply compared to past years. Italy remains the most heavily impacted nation, registering 594 confirmed cases and 41 fatalities according to the Instituto Superior de Sanidad (ISS). Of those Italian cases, 306 involve neuroinvasive manifestations, which represent the most severe clinical presentation of the infection. Five of these neuroinvasive episodes were classified as imported cases originating from the Maldivas, Francia, Bélgica, Grecia, and Países Bajos. Furthermore, Italian screening protocols identified 81 asymptomatic infections among blood donors, alongside 202 febrile cases—including one imported from Burkina Faso—and four other symptomatic presentations.
The case fatality rate for autochthonous (locally acquired) neuroinvasive forms in Italy currently stands at 13,3 %, marking a slight decrease from the 15 % rate recorded during the equivalent period in 2025. At this juncture last year, Italy had documented 582 cases and 39 deaths, demonstrating an expanded geographic footprint and higher viral activity in the current season.
Meanwhile, the Organización Nacional de Salud Pública in Greece has reported 324 infections and 30 deaths. Six of these fatalities occurred during the last week of the reporting period. Total mortality in Greece for 2026 has surged by 233 % compared to the entire preceding year, when authorities recorded 96 infections and nine deaths. Geographically, transmission is heavily concentrated in the eastern region of Ática and northern suburban districts of Athens, where more than twenty municipalities operate under formal public health alerts.
Wider Continental Spread and Environmental Drivers
Beyond Italy and Greece, additional countries are reporting active transmission chains. Macedonia del Norte has confirmed 43 contagios resulting in five deaths, sustaining continuous epidemiological surveillance across local healthcare networks. In Northern Europe, Países Bajos reported its initial cases in August, culminating in 18 confirmed diagnoses and three fatalities. The appearance of the virus in these northern latitudes underscores how shifting ecological parameters are altering vector habitats.
According to assessments from the World Health Organization (WHO), elevated ambient temperatures driven by global climate change have enabled the mosquito vectors to expand their geographical range.
| Country | Confirmed Cases (2026) | Total Fatalities (2026) | Key Epidemiological Notes |
|---|---|---|---|
| Italy | 594 | 41 | Includes 306 neuroinvasive cases; 81 asymptomatic blood donor detections. |
| Greece | 324 | 30 | Mean age of deceased is 84; heavy concentration in Ática and Athens suburbs. |
| Macedonia del Norte | 43 | 5 | Maintains active surveillance due to localized mortality. |
| Países Bajos | 18 | 3 | First cases detected in August, signaling northern expansion. |
Contraindications & When to Consult a Doctor
Immunocompromised patients and older adults should exercise heightened caution against mosquito exposure.
References
- Instituto Superior de Sanidad (ISS). Weekly epidemiological bulletin on West Nile and Usutu viruses. September 2026.
- Greek National Public Health Organization (EODY). Epidemiological surveillance reports for vector-borne diseases. September 2026.
- World Health Organization (WHO). Climate change and vector-borne disease distribution updates.
