ECDC counted 124 affected areas and 877 locally acquired West Nile virus cases across 15 European countries in 2026. Here is what those figures mean.
West Nile virus in Europe: what the 2026 season shows
West Nile virus is circulating in Europe again this season. The European Centre for Disease Prevention and Control (ECDC) publishes a weekly overview of human infections. Its report for week 35 of 2026 was produced on 27 August 2026 from data submitted up to 26 August 2026. Since the season began, 124 areas affected by the virus have been identified in 15 countries: Italy, Greece, Romania, France, Serbia, Spain, North Macedonia, Croatia, Germany, Albania, Austria, Cyprus, Hungary, Kosovo and the Netherlands. In that one week, 25 areas were reported as affected for the first time this season. Those figures describe where human infection has been recorded, not where every mosquito carries the virus. The European Centre for Disease Prevention and Control reports that these national totals are compiled from human surveillance data.
How ECDC defines an affected area
An affected area is one where at least one locally acquired human case has been reported during the current season. Cases are normally confirmed under the European Union case definition. The weekly table and map rest only on human data reported to EpiPulse Cases, and they exclude animal surveillance. That matters when reading the numbers. A country can look quiet because its human reporting is limited, not because its mosquitoes are free of the virus. ECDC states that the overview exists to support decisions about the safety of blood and substances of human origin under Commission Directives 2004/33/EC and 2014/110/EU. It should not be treated as a comprehensive epidemiological assessment. Equid and bird outbreaks appear in the joint monthly ECDC and EFSA report.
The national picture across Europe
The 15 countries have reported 877 locally acquired human cases this season. Italy accounts for 428, Greece for 222, Spain for 79, North Macedonia for 49, Romania for 45, France for 28 and Serbia for 11. Croatia and the Netherlands each report three, Austria, Cyprus and Germany each report two, and Albania, Hungary and Kosovo each report one. Eight Greek cases have an unknown place of infection. The weeks after this snapshot brought further change. The Istituto Superiore di Sanita reported 432 confirmed human infections in Italy by 26 August, a rise from 312 in its previous report. These counts move weekly, so read any single figure as a dated snapshot rather than a final total.
Where cases cluster in Italy
Italian surveillance shows how unevenly this virus appears. Provinces with demonstrated circulation in vectors, animals or humans rose from 60 in 16 regions to 66 in 17 regions by 26 August 2026. The highest case counts fell in Lombardia with 114, Veneto with 74, Lazio with 63, Piemonte with 60, Emilia-Romagna with 42, Campania with 27 and Sardegna with 20. At province level, Padova recorded 42 cases, Milano 40, Roma 33, Latina 25, Torino 21, Cremona 21 and Oristano 20. Of the 432 confirmed infections, 223 were neuroinvasive, 144 were febrile, 63 were asymptomatic blood donors and two had other symptoms. Seventeen deaths were notified. Case fatality among confirmed neuroinvasive forms was 7.2 percent. Among the neuroinvasive infections, three were imported cases from the Maldives, France and Belgium, and one febrile case was imported from Burkina Faso.
Transmission, risk and who becomes unwell
Mosquitoes acquire the virus by feeding on infected birds. The main European vectors are Culex pipiens and Culex modestus, and most human infections in Europe occur between July and September. Humans and other mammals are incidental, dead-end hosts. Transmission through organ transplantation, blood transfusion, pregnancy and breastfeeding has been documented but is rare. No human to human transmission through everyday contact has ever been recorded. About 80 percent of infections cause no symptoms. Around 20 percent develop West Nile fever, and fewer than 1 percent develop neuroinvasive disease. Advanced age and conditions such as hypertension, diabetes, renal disease and haematological disorders raise the risk of severe illness. There is no specific treatment, so care is supportive.
Symptoms and severity to watch for
West Nile fever can bring fever, headache, tiredness, body aches, nausea or vomiting, and sometimes a rash or swollen lymph glands. Severe disease is different. It can cause high fever, neck stiffness, disorientation, tremors, convulsions, muscle weakness, paralysis or coma. Roughly 1 in 150 infected people develop a severe central nervous system infection, and the case fatality ratio for neuroinvasive disease can reach 17 percent. The World Health Organization (WHO) Regional Director for Europe, Hans Henri P. Kluge, links rising cases to warmer temperatures and longer summers, which give mosquitoes more time and territory to transmit the virus. Anyone with sudden neurological symptoms should seek medical care promptly rather than wait. Seek advice from a clinician, not from an article.
Practical protection and honest limits
Protection rests on reducing bites and removing breeding sites. WHO recommends covering clothing, less time outdoors at dawn and dusk, window and door screens, approved repellents, air conditioning, fans or bed nets, and clearing stagnant water around the home. Physical barriers work when they are correctly specified, intact and correctly used. A damaged screen is not protection. Because no vaccine or specific treatment exists for people, these measures carry real weight, especially for older or immunocompromised relatives. Do not treat absence from a map as absence of risk. Case counts are reported data, and reporting systems differ. Read each figure as a dated snapshot, act on the practical steps, and keep the risk in proportion.
Sources
- Surveillance of West Nile Virus infections in humans in Europe, weekly report, week 35, 2026: European Centre for Disease Prevention and Control
- Report della Sorveglianza dei casi umani di West Nile e Usutu virus in Italia nella stagione 2026: Istituto Superiore di Sanita
- West Nile virus: as cases rise across parts of Europe, here is what you need to know: World Health Organization Regional Office for Europe
- West Nile virus fact sheet: World Health Organization
- Factsheet about West Nile virus infection: European Centre for Disease Prevention and Control
This article is general information, not medical advice. Ask a doctor or pharmacist about your own health.