Italy opens 2026 West Nile season: Caserta and Firenze report the first mainland EU cases

Italy has become the first mainland EU/EEA country to register a locally-acquired West Nile virus case in 2026. Two human cases, one in the province of Caserta (Campania) and the other in the metropolitan area of Firenze (Toscana), were confirmed in the week ending 17 June and folded into the European Centre for Disease Prevention and Control's Communicable Disease Threats Report for week 25, published 18 June. North Macedonia carries the only other 2026 case, a single patient in Vardar reported three weeks earlier, which leaves the EU/EEA regional tally at 2 countries, 3 cases, 3 areas, and (so far) no deaths.

That is the headline in three numbers. The story underneath is more interesting.

What the ECDC W25 weekly actually says

The ECDC's weekly WNV bulletin, a public dashboard refreshed every Thursday during the European transmission season, dropped on 18 June with data current to 17 June. The epidemiological summary is short: "Since the beginning of 2026, and as of 17 June, 2 countries in Europe reported 3 human cases of West Nile virus infection: Italy and North Macedonia." Both Italian cases are new in the W25 cycle; the North Macedonian case is a carry-over from week 24. The 2025 Italian season finished at 779 cases and 72 deaths, a case-fatality ratio of 9.2 percent, and the ECDC's W25 data is the season's first datapoint against that yardstick.

The cases are geographically separate. Caserta sits in Campania, southern Italy, about forty kilometres north of Naples. Firenze, Florence, sits in Toscana, central Italy. They are roughly 450 road kilometres apart, on different coasts, with different regional health authorities, different climate zones (coastal-Mediterranean versus sub-Apennine), and different vector ecology. The fact that the two cases landed in the same week in two unrelated areas is the structural signal, not the coincidence; it is consistent with what the Italian surveillance system has been warning since week 23, when the season was formally declared open.

What Italian local press confirms

The ECDC weekly reports aggregated case counts, not the people. Italian local press filled in the human details within days of each confirmation.

Il Tirreno reported on or around 12 June that a woman had been hospitalised in Firenze after testing positive for West Nile virus in Bagno a Ripoli, a comune of about 25,000 people on the southern edge of the Florence metropolitan area. The Tuscany regional health authority activated the local mosquito-control plan, which in Italy is the same basic instrument used every summer in the Po Valley and along the Tyrrhenian coast: larvicide treatment of public catch basins, ultra-low-volume adulticide spraying in a 200-metre buffer around the case's home, door-to-door information in the affected streets, and clinical surveillance of any fever of unknown origin presenting in the catchment area within the following two weeks.

Fanpage and il Fatto Vesuviano reported the Campania case separately, identifying the patient as a 70-year-old man from Grazzanise, a town of around 7,000 in the province of Caserta, and confirming it as the first 2026 human case in the region. The Campania regional health authority did what the Tuscany authority did: same playbook, same 200-metre buffer, same larvicide-plus-adulticide sequence.

There is no public confirmation yet of either patient's clinical course, and the ECDC weekly is consistent with the regional reports, with no deaths and no neuroinvasive complications disclosed at the time of writing.

Why 2026 looks earlier than 2025

Last year's Italian season peaked in late August and early September, with 779 confirmed cases and 72 deaths reported across 9 regions. The 2026 season is opening roughly six to eight weeks earlier, depending on which region you measure from. That is not, on its own, a crisis. It is a trend.

Three drivers get cited in the European climate-and-vector literature, and they are not mutually exclusive. Warmer winters allow Culex pipiens, the common European house mosquito and the principal WNV vector in Italy, to overwinter more efficiently and to reach adult density earlier in the spring. Longer and warmer summers extend the adult-biting season at the other end. And the bird-mosquito-bird cycle that maintains the virus through the year picks up intensity as the mosquito population grows. The 4 June 2026 AGI (Agenzia Giornalistica Italia) analysis of Italian temperature-infectious-disease correlations, reporting the now-frequently-cited 20-percent-per-degree figure for the rise in vector-borne infection risk, sits in this frame, as does the European Centre's own 2026 Communicable Disease Threats Report preamble on the continental vector season.

The practical consequence is that "West Nile season" is no longer a phrase confined to late summer. The 2026 calendar opened the surveillance window in week 23, and the first human cases arrived in week 25, a two-week gap, consistent with the standard delay between mosquito infection and human symptomatic confirmation.

What to watch in the next four weeks

The next three ECDC weekly bulletins, W26 (data to 24 June, expected Friday 26 June), W27 (data to 1 July), and W28 (data to 8 July), will be the season's first real stress test. The 2025 baseline points to Greece, Romania, Hungary, Serbia, and Spain as the most likely next countries to report. If the season's trajectory matches last year's, the Italian total will be in the low double digits by the end of July and in the hundreds by mid-September.

For individual readers in Italy, the operative advice has not changed in a decade: cover up at dusk and dawn, use a proven repellent on exposed skin, empty standing water from balconies and gardens, sleep under treated netting or in screened rooms in rural areas. For readers elsewhere in southern and central Europe, the early-2026 Italian data is the first concrete signal that this season is starting earlier than last; not a reason to panic, and not a reason to ignore.

What we know

• 2 countries in Europe have reported 2026 human West Nile virus cases, per the ECDC Communicable Disease Threats Report Week 25 (released 18 June 2026, data to 17 June 2026): Italy (2 cases) and North Macedonia (1 case). Total: 3 cases, 3 areas, 0 deaths.
• Italy's 2 cases are in Caserta (province of Caserta, Campania), a 70-year-old man from Grazzanise, and Firenze (metropolitan area, Toscana), a woman in Bagno a Ripoli. Confirmed by Italian regional health authorities and reported in Italian local press on or around 12 to 14 June 2026.
• This is the first mainland EU/EEA country to report locally-acquired 2026 WNV cases. North Macedonia (Vardar, 1 case) is non-EU/EEA; Italy is the first EU/EEA member state. ECDC W25 weekly
• The 2025 Italian season finished at 779 cases, 72 deaths, CFR 9.2 percent across 9 regions, per the ISS integrated surveillance system. The 2026 season is opening 6 to 8 weeks earlier than the 2025 peak. EpiCentro ISS
• Italy's 2026 integrated surveillance plan (Piano Nazionale Arbovirosi) formally opened the season in week 23; the first human cases arrived in week 25, a two-week gap, consistent with the standard delay between mosquito infection and human symptomatic confirmation.

What to do

• For residents of Caserta, Firenze, or any other Italian municipality currently within a confirmed 200-metre case buffer: the regional health authority is already running the standard Italian playbook (larvicide treatment of public catch basins, ultra-low-volume adulticide spraying around the case's home, door-to-door information, two-week clinical surveillance of any fever of unknown origin). Cooperate with the larvicide teams, empty any standing water on your balcony or in your garden the same day you hear about a local case, and bring any fever of unknown origin within the next two weeks to your GP or ASL front office without waiting it out. The EpiCentro integrated surveillance system is the source of truth; your regional ASL site is the operating layer.
• For residents elsewhere in Italy, especially in the historical WNV belt (Po Valley, Tyrrhenian coast, Sardinia, Sicily) and in any of the 9 regions that reported 2025 cases: the season is opening earlier than last year, so the personal-protection window is longer, not shorter. Cover up at dusk and dawn, use a proven repellent (DEET, picaridin, IR3535, or oil of lemon eucalyptus) on exposed skin, empty standing water weekly from balconies, garden pots, and gutters, and sleep under treated netting or in screened rooms in rural and peri-urban areas. The 200-metre buffer is the public instrument; your own perimeter is the personal one. Both layers are useful.
• For clinicians and GPs in Italian catchment areas: the ECDC W25 weekly and the EpiCentro ISS integrated surveillance portal are the upstream signals. Any fever of unknown origin in a patient resident in, or recently returned from, a 2026 affected NUTS3 area (ITF31 Caserta, ITI14 Firenze) between June and October should be WNV-tested. Neuroinvasive presentations (meningitis, encephalitis, acute flaccid paralysis) carry a higher case-fatality ratio and should be escalated per the Piano Nazionale Arbovirosi 2026 protocol. Blood-donor deferral rules apply in affected provinces.
• For travelers to Italy this summer (northern hemisphere June to September): the affected areas are rural and peri-urban, not the main tourist corridors. Standard travel-medicine precautions (DEET- or picaridin-based repellent, long sleeves at dusk, screened or netted accommodation in rural areas) are sufficient. There is no travel advisory against Tuscany or Campania at this stage. Pregnant travellers and immunocompromised travellers should consult their travel-medicine clinic for the latest regional ASL guidance.
• For anyone reading from elsewhere in southern and central Europe (southern France, Spain, Greece, the Balkans): Italy's W25 cases are the first mainland EU/EEA signal of the 2026 season, but they are not the only signal. The 2025 baseline is 9 Italian regions plus Greece, Romania, Hungary, Serbia, and Spain. ECDC W26 (data to 24 June, expected Friday 26 June 2026) will be the next continental checkpoint; local press in your own country is the fastest regional signal. Personal protection is portable.

Sources cited

1. ECDC Communicable Disease Threats Report Week 25 (13 to 18 June 2026), West Nile virus infection weekly bulletin, data to 17 June 2026, published 18 June 2026. https://wnv-weekly.ecdc.europa.eu/
2. ECDC Surveillance Atlas of Infectious Diseases: West Nile virus infection, current season (2026). https://www.ecdc.europa.eu/en/west-nile-virus-infection/surveillance-and-disease-data
3. EpiCentro (Istituto Superiore di Sanità) Arbovirosi in Italia: sorveglianza integrata nazionale, Piano Nazionale Arbovirosi 2026. https://www.epicentro.iss.it/arbovirosi/
4. Fanpage "Uomo positivo al virus West Nile in Campania, è il primo caso del 2026: è un 70enne di Grazzanise" (around 13 June 2026). https://www.fanpage.it/napoli/uomo-positivo-al-virus-west-nile-in-campania-e-il-primo-caso-del-2026-e-un-70enne-di-grazzanise/
5. Il Tirreno republished via MSN "Firenze, caso di West Nile a Bagno a Ripoli: paziente ricoverata, scatta il piano contro le zanzare" (around 12 June 2026). https://www.msn.com/it-it/notizie/italia/firenze-caso-di-west-nile-a-bagno-a-ripoli-paziente-ricoverata-scatta-il-piano-contro-le-zanzare
6. il Fatto Vesuviano "West Nile, primo caso del 2026 in Campania" (around 14 June 2026). https://www.ilfattovesuviano.it/
7. Mosticare threat-map data room, live, post-MOS-2166 W25 fold-in, 19 June 2026 21:59 UTC. IT WNV 2026 row 0 shows 2 cases in NUTS3 areas ITF31 Caserta/Campania and ITI14 Firenze/Toscana. https://mosticare.org/threat-map/feed.json
8. AGI (Agenzia Giornalistica Italia) "Pazzo clima, per ogni grado in più sale del 20 percento il rischio infezioni" (4 June 2026), Italian consumer-press anchor for the warming-as-driver frame. https://www.agi.it/salute/notizie/pazzo-clima-per-ogni-grado-in-piu-sale-del-20percento-il-rischio-infezioni-2026-06-04.html