Italy opens 2026 West Nile season: Caserta and Firenze report the season's first cases

Italy has reported its first locally-acquired West Nile virus cases of the 2026 season. Two human cases, one in the province of Caserta (Campania) and the other in the metropolitan area of Firenze (Toscana), were confirmed in mid-June and folded into the European Centre for Disease Prevention and Control's Communicable Disease Threats Report for the week of 13 to 18 June 2026, published 18 June.

That is the headline. The story underneath is more interesting.

What the ECDC W25 weekly actually says

The ECDC's Communicable Disease Threats Report for the week of 13 to 18 June 2026 was published on 18 June. Its West Nile virus update marks the start of the European season. The 2025 Italian season finished at 779 confirmed cases and 72 deaths, a case-fatality ratio of 9.2 percent (ECDC historical data), and the two June cases are the season's first datapoint against that yardstick.

The cases are geographically separate. Caserta sits in Campania, southern Italy. Firenze, Florence, sits in Toscana, central Italy. They sit under different regional health authorities, in different climate zones (coastal-Mediterranean versus sub-Apennine), with 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.

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.

The Comune di Bagno a Ripoli confirmed on 12 June that an adult woman had been hospitalised, in good clinical condition, 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 and adulticide spraying around the case's home.

Fanpage reported the Campania case, identifying the patient as a 70-year-old man from Grazzanise in the province of Caserta, and confirming it as the first 2026 human case in the region.

There is no public confirmation yet of either patient's clinical course, and no deaths or neuroinvasive complications have been disclosed at the time of writing.

Why 2026 looks earlier than 2025

Last year's Italian season produced 779 confirmed cases and 72 deaths, a case-fatality ratio of 9.2 percent, Italy's largest WNV season on record (ECDC historical data). Italian surveillance had confirmed the first two human cases of the new season by mid-June. 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. Culex pipiens, the common European house mosquito and a major WNV vector in Europe, overwinters as mated females in frost-free shelters and is abundant from mid-spring to the first frosts. 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 rise in vector-borne infection risk with warming 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 first human cases of the 2026 season were confirmed in mid-June.

What to watch in the next four weeks

The countries that reported cases in 2025, among them Greece, Romania, Hungary, Serbia, and Spain, are the countries to watch as the season develops (ECDC historical data).

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 of the new season; not a reason to panic, and not a reason to ignore.

What we know

• Italy confirmed its first two locally-acquired West Nile virus cases of the 2026 season in mid-June. The ECDC Communicable Disease Threats Report for the week of 13 to 18 June 2026 (released 18 June 2026) carries the season's West Nile virus update.
• The Italian cases are a 70-year-old man from Grazzanise (province of Caserta, Campania) and a woman in Bagno a Ripoli (metropolitan area of Firenze, Toscana). Confirmed by Italian regional health authorities and reported in Italian local press on or around 12 to 14 June 2026, with disinfestation under way in Bagno a Ripoli.
• The 2025 Italian season finished at 779 cases, 72 deaths, CFR 9.2 percent, Italy's largest WNV season on record. ECDC historical data

What to do

• For residents of Caserta or Firenze: the regional health authority is already running the standard Italian playbook (larvicide treatment of public catch basins and adulticide spraying around the case's home). 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 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 the Italian regions that reported 2025 cases: the season is under way, so the personal-protection window is open. 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 public spray programme 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 weekly report 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, an area with local West Nile virus circulation 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 an early signal of the 2026 season, but they are not the only signal. The 2025 baseline includes Italy, Greece, Romania, Hungary, Serbia, and Spain (ECDC historical data); 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, covering 13 to 18 June 2026, published 18 June 2026; West Nile virus update. https://www.ecdc.europa.eu/en/publications-data/communicable-disease-threats-report-13-18-june-2026-week-25
2. ECDC Surveillance and disease data: West Nile virus infection, current season (2026). https://www.ecdc.europa.eu/en/infectious-disease-topics/west-nile-virus-infection/surveillance-and-updates-west-nile-virus
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. Comune di Bagno a Ripoli, "Un caso di West Nile a Bagno a Ripoli, in corso interventi di disinfestazione" (official communique, 12 June 2026). https://www.comune.bagno-a-ripoli.fi.it/novita/comunicati/un-caso-di-west-nile-bagno-ripoli-corso-interventi-di-disinfestazione
6. ECDC, Historical data on local transmission in Europe for West Nile virus (2025 season: Italy's 779 confirmed cases, 72 deaths, 9.2% case-fatality ratio). https://www.ecdc.europa.eu/en/west-nile-fever/surveillance-and-disease-data/historical
7. ECDC, Culex pipiens, factsheet for experts (major vector of West Nile virus in Europe; overwinters as mated females). https://www.ecdc.europa.eu/en/infectious-disease-topics/related-public-health-topics/disease-vectors/facts/mosquito-factsheets/culex-pipiens