West Nile virus in Europe 2026: what you need to know

Of the mosquito-borne diseases that recur in Europe every summer, West Nile virus (WNV) is the one that asks the narrowest question of a household in Italy, Greece, Romania, Spain, or North Macedonia between July and September: can a Culex mosquito reach the bedroom between dusk and dawn? The protection answer is structural, not pharmaceutical, and it is the same answer in every affected country. This hub is the entry point to the Mosticare 2026 West Nile virus coverage: it describes the disease, the vector, the 2026 season so far, the protection layer that sits in the home, and the consumer-protection framing that is the only available line of defence for a pathogen with no human vaccine and no specific antiviral.

The page is intentionally evergreen. The country sections, the vector behaviour, the clinical spectrum, and the household protection logic do not change with the headline case counts. The week-by-week surveillance signal changes, and the Mosticare threat-map data feed (https://mosticare.org/threat-map/data) carries the live numbers. The durable piece is this page; the moving piece is the data.

What West Nile virus is

West Nile virus is a flavivirus maintained in a bird-mosquito-bird transmission cycle. Culex mosquitoes, chiefly Cx. pipiens in continental Europe and Cx. molestus in urban environments, pick up the virus when they feed on infected birds and pass it on when they subsequently feed on humans, horses, and other incidental hosts. Humans and horses are dead-end hosts: they do not sustain transmission. The disease is not contagious person-to-person, is not food-borne, and is not water-borne [ECDC WNV infection page; WHO WNV fact sheet].

Three things West Nile virus is not, and the misreads cost households real protection:

• Not a tropical disease. It is established endemically across southern and southeast Europe. The first major European outbreaks were recorded in Romania in 1996 and in Volgogradgrad (Russia) in 1999. Southern France and northern Italy followed in the early 2000s. Greece had its first large outbreak in 2010. Every year since, the ECDC weekly West Nile virus monitoring has had something to record.
• Not dengue, not chikungunya. Those two are Aedes albopictus viruses, day-biting, container-breeding, with different geography and different protection patterns. Mixing them up is one of the more common errors in European consumer press. The protection logic for Aedes-borne viruses (daytime terrace and garden) and Culex-borne WNV (night-time bedroom) is different.
• Not preventable by vaccines available to the public. There is no human vaccine against WNV licensed for the general European population. Equine vaccines exist and are used in horses; that is a separate programme run by national veterinary authorities. The protection layer for people sits in the household, not in the clinic.

The 2026 season in one paragraph

The European Centre for Disease Prevention and Control published its first standalone weekly West Nile virus case-data report of the 2026 EU/EEA season on 2 July 2026, with a data cutoff of 1 July. As of that report, six cases had been recorded across three countries: Italy with three, Romania with two, and North Macedonia with one [ECDC WNV weekly, Week 27]. Romania's entry onto the platform was the structural signal that the pan-European autochthonous-transmission window had formally opened for the season.

By the ECDC week-28 Communicable Disease Threats Report, covering 6 to 10 July 2026, the picture had materially widened. As of 8 July, ECDC recorded that 11 areas affected by West Nile virus had been identified in five countries across Europe: Italy with five, North Macedonia with two, Romania with two, Greece with one, and Spain with one. Greece and Spain were first-time 2026 entries, Italy had moved from three to five affected areas, and ECDC framed the trajectory plainly: "seasonal weather conditions are currently favourable for mosquito-borne transmission," so "more cases are expected to occur in the coming weeks" [ECDC CDTR, week 28; ECDC WNV weekly, as of 8 July].

Across the Atlantic, the United States is providing the parallel signal. CDC's current-year West Nile virus dashboard, data current to 7 July 2026, records 48 human cases reported through end-June, 38 of them neuroinvasive, across 23 states, with Arizona's Maricopa County as the early-season epicentre. CDC has described the early season as the highest in roughly 22 years [CDC WNV current-year data, 7 July 2026]. The United States sits outside Mosticare's primary European, Mediterranean, and Sahel editorial footprint, so it is noted as a transatlantic seasonal-severity peg, not as a European-market claim. What travels across the Atlantic is a shared biology: WNV is carried by Culex mosquitoes on both continents, and an early, neuroinvasive-heavy season is a signal about vector activity under warm conditions.

The vector: Culex pipiens and the dusk-to-dawn window

The species doing the work in continental Europe is Culex pipiens, the common house mosquito. It is small, brown, unremarkable, and, unlike Aedes albopictus, it is nocturnal. Its biting activity peaks in the two hours after sunset and the two hours before sunrise, with a quieter but non-zero background through the night. The same species will rest during the day in shaded vegetation, cellars, sheds, and the cooler corners of inhabited buildings.

Three behavioural facts about Cx. pipiens drive the household protection logic:

1. It is a dusk and night feeder. This is the critical distinction from Ae. albopictus. An open bedroom window at 22:00 in August in Pavia, Thessaloniki, Bucharest, Plovdiv, or Slavonski Brod is an open invitation.
2. It breeds in standing water that is not container-sized. Where Ae. albopictus uses small container water (a flowerpot saucer, a bottle cap), Cx. pipiens uses larger accumulations: blocked drains, flooded cellars, irrigation overflow, neglected ponds, used tyres laid flat, and any organically rich standing water in urban and peri-urban settings. Source reduction works on Culex but looks different from Aedes source reduction.
3. It enters the house. Unlike Ae. albopictus, which tends to feed outdoors, Cx. pipiens readily enters bedrooms through open windows, doors left ajar for ventilation in summer, and unsealed gaps around window frames. Indoor biting is the rule, not the exception, for WNV-relevant transmission.

The corollary, for every household in the five-country 2026 footprint: the protection question for July through September is not "what do I put on my skin during the day." It is "what is between me and a Culex mosquito between dusk and dawn."

The countries where this matters in 2026

The European Centre for Disease Prevention and Control's 2026 week-28 weekly records affected areas in five countries. Each one is a country with a documented history of locally acquired WNV transmission, and each one carries its own national surveillance infrastructure and its own reporting cadence. The country landings linked from this hub carry the per-country detail; the table below is the overview.

The 2025 Italian baseline was 779 cases and 72 deaths across nine regions, with a case-fatality ratio of 9.2 percent [EpiCentro ISS arbovirosi portal]. The 2024 pan-European baseline carried significant transmission in Austria, Hungary, Serbia, and Romania. The 2026 trajectory is structurally tracking the early, broad opening that the climate and land-cover models predicted, with Romania's week-27 entry as the central-eastern European inflection signal and the week-28 expansion as the southern and western European widening.

Symptom spectrum and when to call a doctor

About 80 percent of human WNV infections are asymptomatic. Of the remaining 20 percent, the great majority present as a self-limiting febrile illness, West Nile fever, with fever, headache, muscle aches, fatigue, and sometimes a maculopapular rash. The incubation period is typically 2 to 14 days. Symptoms last 3 to 6 days in most cases.

Fewer than 1 percent of infected individuals develop neuroinvasive disease, West Nile neuroinvasive disease (WNND), which presents as meningitis, encephalitis, or acute flaccid paralysis. Older adults (above 60), people with immunosuppression, and people with chronic conditions (diabetes, hypertension, chronic kidney disease) are at materially higher risk of neuroinvasive disease and of severe outcomes. A 2026 clinical review from Rome's Spallanzani Institute, published in Reviews in Medical Virology (PMID 42431607), reports that the neuroinvasive form carries a case-fatality rate as high as 17 percent, with a higher long-term neurological and functional burden among survivors. There is no specific antiviral treatment for WNV. Clinical management is supportive [Spallanzani Institute review, 2026; ECDC WNV factsheet; WHO WNV fact sheet].

The clinical decision point is therefore early recognition, particularly in older or immunocompromised household members developing high fever, neck stiffness, confusion, weakness, or seizures within the typical transmission season, and prompt presentation to emergency services.

The protection layer that exists in your house tonight

The protection layer for WNV in a SE EU household is built from four components. None of them is new. All of them are physical, and none relies on a new chemical exposure.

1. A mosquito net over the bed. For sleeping adults and children in the WNV transmission season, an untreated mosquito net draped over the bed is the single most reliable chemical-free barrier to Culex bites. Properly tucked under the mattress or with a framed canopy, the net eliminates indoor-biting exposure for the hours when Cx. pipiens is most active.
2. Screens on bedroom windows and doors. Tight-fitting insect screens on the bedroom windows and on any door left open for cross-ventilation in summer prevent Culex from entering the room in the first place. Aluminium-frame fibreglass screens of 16 by 18 mesh or finer are the European residential standard.
3. Elimination of Culex breeding sites in the immediate vicinity. This is different from Aedes source reduction. Cx. pipiens uses larger and more organically rich standing water: blocked roof gutters, neglected ponds, water-filled containers that have been in place for weeks, used tyres stored flat, flooded cellars, and any standing water that has been undisturbed for ten days or more. A weekly walk around the house and garden to drain, dry, or treat these accumulations reduces the local biting pressure.
4. Personal protection during outdoor evening hours. Where presence on the terrace, in the garden, or at an outdoor event during the dusk-to-dawn window is unavoidable, personal protection (long sleeves, long trousers, light-coloured clothing, and an age-appropriate skin repellent applied according to label) is the third line of defence. The first line is the bedroom net; this is the supplementary one.

What the protection layer is not: it is not a prescription, not a vaccination, not a chemical indoor treatment. The chemical layer (residual indoor spraying, outdoor ultra-low-volume adulticiding, larviciding of standing water with Bacillus thuringiensis israelensis or insect growth regulators) is a public-health tool used by municipal vector control. It complements, but does not replace, the household physical-barrier layer.

Why bedroom nets, and the regulatory frame around them

For households in the SE EU transmission zone, the relevant barrier products sit in two regulatory families.

Untreated nets, the polyester or cotton mosquito nets, framed canopies, and gazebo nets used over beds and around outdoor seating, are general textile products. They make no chemical claims. They carry no biocidal-product registration. They are the simplest, longest-lasting, and most easily maintained part of the household barrier. They are what a family with a baby, a toddler, an elderly relative, or an allergic individual can deploy tonight.

Treated nets, insecticide-treated nets (ITNs), are a different product family. They carry a permethrin or other pyrethroid treatment, fall under the European Biocidal Products Regulation (BPR, Regulation (EU) No 528/2012), and in the global public-health context carry WHO prequalification status for use against malaria vectors in endemic tropical settings. WHO prequalification and BPR conformity apply only to treated nets, never to untreated household products. Untreated bed canopies, gazebo nets, and baby or crib canopies are not WHO-prequalified products, are not BPR-registered biocidal products, and do not claim to be [European Commission Regulation (EU) No 528/2012 (BPR); WHO Guidelines for malaria].

For households in the SE EU WNV zone, untreated nets over the bed, plus screened windows, plus source reduction around the house, are the complete physical-barrier layer. Where a household has a specific need for additional protection (immunocompromised family members, very elderly relatives, prior history of severe mosquito-borne illness) the conversation about treated products is one to have with the treating physician and with reference to the locally labelled BPR-registered products.

Frequently asked questions

Question: Is West Nile virus dangerous? About 80 percent of infections cause no symptoms at all. Of those that do, most are a self-limiting fever. Fewer than 1 percent become neuroinvasive, but that form can be severe, and the Spallanzani Institute 2026 review reports a case-fatality rate as high as 17 percent for the neuroinvasive form. Older adults and immunocompromised household members are at higher risk of severe disease.

Question: Can I be vaccinated against West Nile virus? No. There is no human vaccine against WNV licensed for the general European population. Equine vaccines exist for horses. The protection layer for people is household-level physical barriers plus source reduction.

Question: When is the West Nile virus season in Europe? The European transmission season runs from late June through October, with the peak in August. ECDC's weekly West Nile virus monitoring runs from June through November each year. The 2026 season formally opened in week 27 (data cutoff 1 July).

Question: Where in Europe is West Nile virus circulating in 2026? As of 8 July 2026, ECDC records affected areas in five countries: Italy, North Macedonia, Romania, Greece, and Spain. Greece and Spain are first-time 2026 entries. The Mosticare Foundation threat-map data feed at https://mosticare.org/threat-map/data carries the live numbers.

Question: Is a mosquito net enough to protect my family? An untreated mosquito net over the bed, plus tight-fitting window and door screens, plus elimination of Culex breeding sites around the home, plus age-appropriate repellent use during outdoor evening hours, is the complete household protection layer for the WNV season. Each component adds to the others; the combination is what works.

Question: Does DEET work against the mosquitoes that carry West Nile virus? DEET and picaridin are effective repellents against Culex mosquitoes and are recommended by ECDC, CDC, and national public-health authorities for use on exposed skin during the dusk-to-dawn window. They are an effective supplement to a physical barrier, not a replacement for one.

Question: Are the Spanish and Greek 2026 entries a sign that the season is bigger than usual? ECDC's week-28 framing is that seasonal weather conditions are currently favourable for mosquito-borne transmission and that more cases are expected. Greece and Spain are first-time 2026 entries in the weekly section, each with one affected area, which is a signal about geographic spread. Whether the 2026 season ends above or below the multi-year average will only be known at season close.

How to use this hub

This page is the entry point to the Mosticare 2026 West Nile virus coverage. It does not change with the case count of any single week. The country landings (Italy 2026, Greece 2026, Romania 2026) carry the per-country case data and the per-country household guidance. The protection guide (How to protect yourself from West Nile virus mosquito bites) carries the household-layer detail. For the live weekly figures, the right place to look is the ECDC West Nile virus weekly monitoring for the EU/EEA aggregate, the national reference (ISS for Italy, EODY for Greece, INSP for Romania, the national authorities for Spain and North Macedonia) for country-specific case counts and affected-area updates, and the Mosticare Foundation threat-map data feed at https://mosticare.org/threat-map/data for the consumer-facing summary aligned to the same data.

The structural facts do not change. Culex pipiens bites at dusk and through the night. WNV transmits through that bite. An untreated net over the bed breaks the chain. A screened window keeps the mosquito out in the first place. Source reduction around the house lowers the local biting pressure. These four moves, deployed every summer in the SE EU WNV window, are what every household in the affected region has under its own control.

Sources

• European Centre for Disease Prevention and Control. West Nile virus infection, surveillance and disease data, current 2026 season.
• European Centre for Disease Prevention and Control. West Nile virus weekly case-data report, Week 27, 2 July 2026 (data cutoff 1 July 2026).
• European Centre for Disease Prevention and Control. Communicable Disease Threats Report, 19 to 26 June 2026, Week 26.
• European Centre for Disease Prevention and Control. Communicable Disease Threats Report, 6 to 10 July 2026, Week 28.
• European Centre for Disease Prevention and Control. Factsheet about West Nile virus for the general public.
• World Health Organization. West Nile virus fact sheet, continuously updated.
• World Health Organization. Guidelines for malaria, consolidated, the framework on insecticide-treated nets in endemic tropical settings.
• Istituto Superiore di Sanità, EpiCentro. Arbovirosi in Italia: sorveglianza integrata nazionale, Piano Nazionale Arbovirosi 2026.
• Hellenic National Public Health Organization (EODY). Weekly West Nile virus epidemiological surveillance reports, June to October.
• National Institute of Public Health, Romania (INSP). West Nile virus surveillance updates.
• Spallanzani Institute, Rome. West Nile neuroinvasive disease: current management and emerging therapies, Reviews in Medical Virology, 2026. PMID 42431607.
• Centers for Disease Control and Prevention. West Nile virus current-year data, dashboard data current to 7 July 2026.
• European Commission. Regulation (EU) No 528/2012 concerning the making available on the market and use of biocidal products (BPR).
• Mosticare Foundation. Threat-map data feed, weekly publication aligned with ECDC and national public-health authority updates.