Italy leads Europe in West Nile virus cases with 714+ infections in 2025. Complete guide to regional mosquito risks, WNV hotspots, and tourist advice for Italy.

Mosquitoes in Italy: Europe's Ground Zero for Mosquito-Borne Disease

No country in Europe has a longer, deeper, or more consequential relationship with invasive mosquitoes than Italy. The Asian tiger mosquito (Aedes albopictus) established itself in the country in 1990 -- earlier than any other European nation -- and in the decades since, Italy has become the continent's undisputed epicentre for mosquito-borne disease.

In 2025, Italy reported 714 confirmed West Nile virus (WNV) infections and 48 deaths, the highest count at that point in the season. The country's unique combination of geography, climate, and mosquito diversity makes it a bellwether for what the rest of Europe can expect as climate change expands vector range northward.

Italy's Mosquito Landscape

Italy supports populations of both major invasive mosquito species of concern in Europe:

Aedes albopictus (Asian tiger mosquito): Established nationwide since the early 1990s. This daytime-biting species transmits dengue, chikungunya, and Zika. Italy experienced Europe's first chikungunya outbreak (Emilia-Romagna, 2007) and a second outbreak in Lazio and Calabria in 2017.
Culex pipiens (common house mosquito): The primary vector for West Nile virus. Abundant across the Po Valley, coastal wetlands, and irrigated agricultural zones throughout central and southern Italy.

Italy was the first country in Europe to experience large-scale arboviral outbreaks transmitted by locally established mosquito populations, and it continues to record more cases annually than any other EU member state.

West Nile Virus: Italy's Persistent Epidemic

West Nile virus has become an annual reality in Italy. The country accounts for the majority of Europe's WNV cases in most years, and the trend is worsening.

2024 Season

In 2024, Italy reported 455 locally acquired WNV infections out of 1,436 total European cases -- approximately one-third of the continent's burden. The cases were concentrated in the northern regions, particularly the Po Valley, where Culex mosquito populations thrive in the irrigated rice paddies and wetlands.

2025 Season: A Record-Breaking Year

The 2025 season exceeded all expectations. As of October 2025, the ECDC and EFSA reported 714 confirmed WNV infections in Italy, including 48 fatalities (a case fatality rate of 6.7%).

The 2025 outbreak was remarkable for its geographic shift. While previous seasons concentrated in the Po Valley and Emilia-Romagna, the 2025 outbreak hit central and southern Italy hardest:

Lazio: 218 cases, including 171 confirmed autochthonous infections between July and August 2025, with provinces including Latina, Roma, and Frosinone severely affected. Of the Lazio cases, 110 presented as WNV fever, 57 as neuroinvasive disease, and 9 resulted in death.
Campania: 106 confirmed cases across the provinces of Napoli, Caserta, Salerno, and Avellino -- a region that had seen minimal WNV activity in previous years.
Emilia-Romagna and Veneto: Traditional hotspots continued to report significant case numbers.

Researchers have described the 2025 season as a potential hallmark of climate change, with warmer-than-average temperatures and altered precipitation patterns creating ideal conditions for Culex mosquito proliferation.

Regional Variation: A Country of Many Mosquito Realities

Italy's diverse geography means mosquito risk varies substantially by region.

Northern Italy: The Po Valley

The Po Valley remains Italy's WNV heartland. The flat, irrigated agricultural landscape -- particularly rice cultivation in Lombardy, Piedmont, and Veneto -- provides vast breeding habitat for Culex mosquitoes. Cities like Milan, Turin, Verona, and Venice all fall within the high-risk zone.

The integrated One Health surveillance programme in Veneto has been tracking WNV and Usutu virus across human, animal, and mosquito populations since 2010, making it one of the most comprehensive surveillance systems in Europe.

Central Italy: The New Frontier

The 2025 Lazio outbreak revealed that central Italy is increasingly at risk. Rome's urban sprawl, combined with peri-urban green spaces and the Tiber River basin, creates conditions suitable for both Culex and Aedes mosquitoes.

The Lazio outbreak was distinguished by the severity of neuroinvasive cases, with a significant proportion of patients developing encephalitis, meningitis, or acute flaccid paralysis.

Southern Italy and the Islands

Southern regions including Campania, Puglia, Calabria, and Sicily have seen rising case counts. The 2017 chikungunya outbreak in Lazio and Calabria demonstrated that southern Italy can sustain local transmission of Aedes-borne viruses.

Sardinia, while less affected by WNV, supports dense tiger mosquito populations along the coast and in tourist areas.

Tourist Hotspots

Popular tourist destinations each present distinct mosquito profiles:

Rome: Dual risk from Culex (WNV) and Aedes (dengue/chikungunya). The 2025 WNV outbreak in Lazio directly affected the greater Rome area.
Florence and Tuscany: Tiger mosquito populations established in urban centres. WNV risk moderate and increasing.
Venice and the Veneto: High WNV risk due to proximity to Po Valley wetlands. The historic city's canals and standing water also support mosquito breeding.
Amalfi Coast and Naples: Growing risk as Campania emerged as a 2025 WNV hotspot.
Sicily: Tiger mosquitoes present throughout the island. WNV detected in mosquito populations.

Italy's Surveillance and Response

Italy operates one of Europe's most sophisticated mosquito surveillance networks, developed in response to its decades-long experience with mosquito-borne disease.

Integrated One Health Approach

Italy's WNV surveillance follows an integrated model monitoring:

Human cases: Through the national infectious disease surveillance system.
Veterinary surveillance: Horses and wild birds are sentinel species for WNV circulation. Equine cases often precede human outbreaks.
Entomological monitoring: Mosquito trapping and viral testing across endemic regions.
Blood supply screening: Italy mandates nucleic acid testing of blood donations in affected areas during the transmission season to prevent transfusion-transmitted WNV.

Municipal Vector Control

Italian municipalities bear primary responsibility for local vector control. Responses include:

Larviciding: Application of biological larvicides in public green spaces, catch basins, and roadside drains. Many northern municipalities conduct scheduled treatments throughout the season.
Adulticiding: Emergency spraying following confirmed human cases. This is typically conducted as ultra-low-volume application of pyrethroids in the evening hours.
Ordinanze comunali: Municipal ordinances requiring citizens and businesses to eliminate standing water on private property. Compliance varies significantly by region.

Public Health Communication

Italian health authorities issue regular updates during the transmission season (typically June through November). The Istituto Superiore di Sanita (ISS) publishes weekly WNV bulletins tracking cases by region.

Tourist Advice for Italy

Visitors to Italy should factor mosquito risk into their travel planning, particularly during the May-to-October season.

Before You Travel

Check current WNV and dengue case reports for your destination region.
Pack DEET or icaridin-based repellent. Italian pharmacies stock repellents, but selection may be limited in smaller towns.
Consider accommodation with air conditioning or screened windows, particularly in the Po Valley and central Italy.

During Your Stay

Apply repellent during dawn and dusk hours (peak Culex activity for WNV) and during the daytime (peak Aedes activity for dengue/chikungunya).
Be aware that outdoor dining, particularly in the evening, increases exposure in WNV-endemic areas.
If visiting Venice, the Amalfi Coast, or lake regions, mosquito exposure near water features is elevated.

After You Return

If you develop fever, headache, or rash within two weeks of returning from Italy, inform your healthcare provider about potential mosquito-borne disease exposure.
Note that the majority of WNV infections are asymptomatic or mild, but neuroinvasive disease can occur, particularly in adults over 50.

The Climate Change Dimension

Italy's mosquito situation is a preview of what much of Europe will face in the coming decades. The European Commission's Joint Research Centre and ECDC have both highlighted Italy as a case study in how climate warming drives mosquito-borne disease emergence.

Key factors accelerating Italy's mosquito crisis:

Temperature increases: Warmer winters reduce mosquito mortality. Earlier springs extend the transmission season.
Urbanization: Italy's dense urban centres provide abundant breeding habitat in the form of catch basins, underground parking garages, and ornamental water features.
International connectivity: Italy's position as a global tourist destination and Mediterranean transit hub means constant importation of viraemic travellers.
Agricultural practices: Irrigated agriculture, particularly rice cultivation in the north, creates vast Culex breeding habitat.

Looking Ahead

Italy's mosquito challenge is not going to diminish. With WNV cases trending upward, dengue importations increasing, and climate change expanding the range and season of both Culex and Aedes mosquitoes, Italy will continue to serve as Europe's early warning system for mosquito-borne disease.

For residents, travellers, and public health authorities alike, the message is clear: mosquito protection in Italy is no longer optional -- it is essential.

Mosquitoes in Italy 2026: Europe's Ground Zero for Mosquito-Borne Disease | Mosticare