# West Nile virus cases rise in Europe and US

> Live situation record from CLSTR: https://clstr.news/situations/diy-natural-home-pest-control
> Updated: 2026-08-03T20:28:58.000Z. Sources: 413. Developments: 56.

Mosquito surveillance in July confirmed a rapid expansion of West Nile virus across Europe and North America. In the Balkans, Macedonia reported two laboratory‑confirmed cases on July 4 and later confirmed ten infections with seven additional suspected cases, three of which are in critical condition. Italy’s Emilia‑Romagna region detected the virus in mosquitoes across six provinces, prompting a heightened alert, while the national report later recorded 84 human infections, 37 neuro‑invasive and two deaths, leading to stricter blood‑donor and organ‑transplant screening. Spain’s Andalusia confirmed virus‑positive Culex mosquitoes in Seville and Almería and issued alerts for multiple municipalities, including Coria del Río and Dos Hermanas, where a neuro‑invasive case was hospitalized. Greece logged its first 2026 case in early July and, by late July, reported 21 confirmed infections—most with neurological complications—triggering mosquito‑spraying campaigns in Glyfada, Orestiada and other districts. In the United States, the season proved the earliest and most severe since 2004, with 48 cases (38 neuro‑invasive) by end‑June, a surge in Arizona (32 cases, five deaths), new cases in California’s Los Angeles and Long Beach counties, severe cases in El Paso, and first human infections reported in Utah, Maryland and Salt Lake County. France confirmed its first locally acquired case in Pyrénées‑Orientales. The European Centre for Disease Prevention and Control recorded 81 locally acquired infections across the continent, the majority in Italy (46) and Greece (21). Researchers in the United States identified a rapid brain‑protective response to West Nile infection, underscoring the need for continued vector control, public‑health alerts and personal‑protection measures throughout the summer. By early August, Italy’s outbreak grew to 84 confirmed infections (including two deaths) with 37 neuro‑invasive cases, spanning eight regions; Lombardy reported the highest tally and virus‑positive mosquitoes were also found in Abruzzo.

## Claims

- EODY has designated Amari, Heraklion, Filothei‑Psychiko and the 1st and 4th districts of Athens as high‑risk municipalities where no human cases have yet been recorded. (corroborated by 23 sources)
- Thirty‑seven patients showed severe central‑nervous‑system involvement (encephalitis, meningitis or acute flaccid paralysis). (corroborated by 19 sources)
- A total of 42 West Nile virus infections have been reported in Greece since the start of the surveillance period. (corroborated by 19 sources)
- Thirteen patients are currently hospitalized: eight in ordinary wards and five in intensive‑care units. (corroborated by 19 sources)
- A total of 42 West Nile virus infections have been reported in Greece since the start of the 2026 surveillance period. (corroborated by 19 sources)
- Twenty‑one new West Nile virus cases were reported during the last week. (corroborated by 19 sources)
- Four patients over age 65 died after developing central‑nervous‑system complications from West Nile virus infection. (corroborated by 18 sources)
- Twenty‑five patients have been discharged from hospitals after treatment for West Nile virus. (corroborated by 18 sources)
- Five cases had mild symptoms without central‑nervous‑system involvement. (corroborated by 18 sources)
- Greece has recorded a total of 42 West Nile virus infections since the start of the 2026 surveillance period. (corroborated by 12 sources)
- Eight cases of West Nile virus have been registered in Macedonia this year. (corroborated by 11 sources)
- EODY classifies the municipalities of Amari, Heraklion, Filothei‑Psychiko and the 1st and 4th districts of Athens as high‑risk zones despite no confirmed human cases. (corroborated by 11 sources)

## Timeline

### 2026-08-03: West Nile virus claims first 2026 death in California as Arizona reports surge in cases

Arizona reports 47 West Nile cases and five deaths; California records its first 2026 West Nile death in Kings County, highlighting severe risk and urging mosquito‑bite prevention.

2 sources. https://clstr.news/cluster/west-nile-virus-claims-first-2026-death-in-california-as-arizona-reports-surge-in-cases

### 2026-08-03: Bulgaria braces for West Nile virus peak, says health expert Iva Hristova

Prof. Iva Hristova says Bulgaria may already have West Nile virus circulating and expects a peak in August‑September, urging mosquito protection and hygiene measures.

4 sources. https://clstr.news/cluster/bulgaria-braces-for-west-nile-virus-peak-says-health-expert-iva-hristova

### 2026-08-02: West Nile Virus Case Confirmed in Dos Hermanas, Spain, Extending Alert Zone

Andalusia confirmed a new West Nile virus case in Dos Hermanas, Spain, bringing total diagnoses to 14 and extending the regional health alert until Aug 30 across 19 municipalities.

5 sources. https://clstr.news/cluster/west-nile-virus-case-confirmed-in-dos-hermanas-spain-extending-alert-zone

### 2026-08-02: Macedonia reports seven suspected West Nile virus cases, three in critical condition

Macedonia's Skopje clinic reports ten confirmed and seven suspected West Nile virus cases; three elderly patients are critical, while health officials monitor the outbreak.

4 sources. https://clstr.news/cluster/macedonia-reports-seven-suspected-west-nile-virus-cases-three-in-critical-condition

### 2026-08-02: West Nile virus cases rise to 84 in Italy, two deaths reported

Italy reports 84 West Nile virus infections, two deaths; cases spread across eight regions with Lombardy most affected, prompting tighter blood‑donation checks and mosquito‑bite prevention advice.

6 sources. https://clstr.news/cluster/italy-records-84-west-nile-cases-and-tightens-blood-donation-screening

### 2026-08-02: Romania confirms first severe West Nile infection and investigates additional cases

Romania reports its first severe West Nile case—a 22‑year‑old from Vaslui—treated in Iași, with two additional suspected patients under investigation and health officials urging early detection during mosquito‑

2 sources. https://clstr.news/cluster/romania-confirms-first-severe-west-nile-infection-and-investigates-additional-cases

### 2026-08-01: US States Report First Human West Nile Virus Cases in 2026

Utah’s Salt Lake County and Maryland each confirmed their first human West Nile virus cases of 2026, urging residents to use repellents and remove standing water as mosquito infections rise.

6 sources. https://clstr.news/cluster/us-states-report-first-human-west-nile-virus-cases-in-2026

### 2026-07-31: West Nile virus cases rise in Seville, prompting expanded alert area

Two new West Nile cases raise infections to 11 in Seville, prompting expanded alert zones and heightened mosquito control after a neurological case is confirmed.

4 sources. https://clstr.news/cluster/west-nile-virus-cases-rise-in-seville-prompting-expanded-alert-area

### 2026-07-31: Oristano reports fourth West Nile fever case in 2026

Oristano province confirms a fourth West Nile fever case in 2026, an 85‑year‑old hospitalized; health authorities start investigations and urge mosquito‑bite prevention.

2 sources. https://clstr.news/cluster/oristano-reports-fourth-west-nile-fever-case-in-2026

### 2026-07-31: West Nile virus cases surge in Greece, Italy and North Macedonia

West Nile virus infections rise in Greece (42 cases, 4 deaths), Italy (21 cases) and North Macedonia (13 cases), prompting travel warnings and mosquito‑control measures across the region.

21 sources. https://clstr.news/cluster/german-foreign-office-warns-of-west-nile-fever-in-italy-greece-and-other-eu-countries

### 2026-07-30: West Nile Virus Activity Surges in US and Canada in 2026

US and Canada see a surge in West Nile virus in 2026, with record mosquito positives in Utah and Orange County, human cases in Santa Clara, Galveston and Toronto, and positive mosquito pools in Niagara and Wes​

10 sources. https://clstr.news/cluster/west-nile-virus-spreads-in-ontario-bird-and-mosquito-positives-and-first-toronto-human-case

### 2026-07-28: Greece records 42 West Nile infections, 4 deaths as cases surge

Greece reports 42 West Nile cases (four deaths) and Italy 84 cases (two deaths) as the virus spreads, prompting high‑risk alerts and mosquito‑control measures.

36 sources. https://clstr.news/cluster/west-nile-virus-highrisk-zones-identified-in-attica-greece

### 2026-07-28: Andalusia reports nine West Nile virus cases as alerts extend

Andalusia confirmed nine West Nile virus cases—all in Sevilla province—adding three new infections, extending alerts to 20‑21 August and urging protective measures.

8 sources. https://clstr.news/cluster/andalusia-expands-west-nile-fever-alerts-as-cases-rise-to-nine

### 2026-07-28: West Nile Virus First Human Cases Reported in Texas and California Counties

Texas and California counties reported their first 2026 human West Nile cases—Tarrant County with neuroinvasive disease and Fresno County via blood‑donor screening—highlighting surveillance efforts as most West

9 sources. https://clstr.news/cluster/west-nile-virus-first-human-cases-reported-in-texas-and-california-counties

### 2026-07-27: West Nile virus prompts health alerts and mosquito‑bite precautions across North America

Health agencies in Canada and the US issue alerts urging mosquito‑bite prevention and symptom monitoring as West Nile virus risk rises this summer.

2 sources. https://clstr.news/cluster/west-nile-virus-prompts-health-alerts-and-mosquitobite-precautions-across-north-america

### 2026-07-27: West Nile virus detected in mosquitoes in Ontario’s Arnprior and New York’s Suffolk County

West Nile virus was found in mosquito samples from Arnprior, Ontario, and Suffolk County, New York, prompting health officials to advise mosquito‑bite prevention and habitat control.

3 sources. https://clstr.news/cluster/west-nile-virus-detected-in-mosquitoes-in-ontarios-arnprior-and-new-yorks-suffolk-county

### 2026-07-26: West Nile neuroinvasive case hospitalized in Naples, Italy

A 77‑year‑old man from Marano, Naples was hospitalized with neuroinvasive West Nile virus; his condition improved and discharge is imminent. The case is the sixth this summer in Campania, amid criticism of a st

13 sources. https://clstr.news/cluster/west-nile-virus-infections-reported-in-romania-and-italy

### 2026-07-25: El Paso reports two new severe West Nile virus cases

El Paso health officials report two new severe West Nile virus cases, raising total severe infections to four in 2026 and urging residents to follow the “Four D” mosquito‑prevention measures.

2 sources. https://clstr.news/cluster/el-paso-reports-two-new-severe-west-nile-virus-cases

### 2026-07-24: West Nile Virus Case Detected in Coria del Río, Spain

A fifth mild West Nile virus case was confirmed in Coria del Río, Spain, extending the health alert to 14 August and adding nearby towns to a four‑week alert with intensified mosquito control.

5 sources. https://clstr.news/cluster/west-nile-virus-case-detected-in-coria-del-ro-spain

### 2026-07-24: West Nile virus cases surge in Italy, Greece and Southern Europe

ECDC reports 81 West Nile cases in Europe, led by Italy (46) and Greece (21). WHO urges mosquito protection as the virus spreads across southern Europe, prompting travel warnings in Spain.

76 sources. https://clstr.news/cluster/west-nile-virus-confirmed-in-macedonia-as-cases-rise-across-europe

### 2026-07-22: West Nile virus cases rise in Southern Europe

WHO alerts to rising West Nile cases in Greece, Italy and other Southern European nations, with dozens of neuroinvasive infections but no deaths; health agencies urge mosquito control and protective measures.

52 sources. https://clstr.news/cluster/greece-confirms-west-nile-virus-case-in-barrivoulasvouliagmeni

### 2026-07-20: Southern California sees surge in West Nile‑carrying mosquitoes

Southern California experiences a spike in West Nile‑carrying mosquitoes and rising Aedes aegypti numbers, leading to two human cases and a large release of modified mosquitoes to curb the season‑long threat.

5 sources. https://clstr.news/cluster/southern-california-sees-surge-in-west-nilecarrying-mosquitoes

### 2026-07-20: Helicopter Aerial Spraying to Combat Mosquitoes Begins in Orestiada, Greece

A three‑day helicopter spraying of insecticide began on 20 July 2026 in Orestiada, Greece, aiming to curb mosquito nuisance and prevent West Nile virus, officials said.

2 sources. https://clstr.news/cluster/helicopter-aerial-spraying-to-combat-mosquitoes-begins-in-orestiada-greece

### 2026-07-18: West Nile virus warning for Greece as summer mosquitoes rise

West Nile virus spreads via mosquito bites in Greece, usually causing mild symptoms but can lead to severe neurological illness in vulnerable groups; prevention and early medical attention are essential.

3 sources. https://clstr.news/cluster/west-nile-virus-warning-for-greece-as-summer-mosquitoes-rise

### 2026-07-18: First West Nile‑positive mosquito batch detected in Ajax, Durham Region

Durham Region health officials report the first mosquito batch of the season testing positive for West Nile virus in Ajax, urging residents to use repellent and eliminate standing water.

3 sources. https://clstr.news/cluster/first-west-nilepositive-mosquito-batch-detected-in-ajax-durham-region

### 2026-07-17: West Nile Virus Study Shows Brain Defense, NY Health Dept Urges Mosquito Precautions

Researchers revealed the brain’s early antiviral response to West Nile virus, while NY health officials urge mosquito‑bite prevention to curb the disease.

3 sources. https://clstr.news/cluster/west-nile-virus-study-shows-brain-defense-ny-health-dept-urges-mosquito-precautions

### 2026-07-17: West Nile virus claims first Romanian death as three cases confirmed

Three West Nile virus cases were confirmed in Romania, one death and two hospitalizations, prompting health warnings amid hot weather.

3 sources. https://clstr.news/cluster/west-nile-virus-claims-first-romanian-death-as-three-cases-confirmed

### 2026-07-16: First locally acquired West Nile case identified in France's Pyrénées-Orientales

France recorded its first locally acquired West Nile virus infection of 2026 in the Pyrénées‑Orientales, the country's first human case this year, according to Santé publique France.

2 sources. https://clstr.news/cluster/first-locally-acquired-west-nile-case-identified-in-frances-pyrnes-orientales

### 2026-07-16: West Nile and dengue alerts spread in Cuba, Mexico, Spain and US

West Nile virus detections trigger alerts in the US and multiple Spanish locales, while dengue monitoring continues in Cuba and Mexico and mosquito plagues spark fumigation efforts in Spain.

7 sources. https://clstr.news/cluster/west-nile-virus-found-in-mosquitoes-in-south-carolina-and-andalusia-prompting-alerts

### 2026-07-16: Glyfada, Greece, launches mosquito spraying after West Nile virus case confirmed

A West Nile virus case in Glyfada, Greece, led to early‑morning mosquito spraying on multiple streets, with authorities urging residents to use repellents and remove standing water.

15 sources. https://clstr.news/cluster/glyfada-implements-mosquito-spraying-after-west-nile-virus-case-confirmed

### 2026-07-15: Utah homeowners urged to adopt preventive pest control

Utah pest experts advise interior, exterior and yard treatments to curb ants, cockroaches, bedbugs and black‑widow spiders, noting larger colonies and milder winters increase risks.

2 sources. https://clstr.news/cluster/utah-homeowners-urged-to-adopt-preventive-pest-control

### 2026-07-13: West Nile virus case confirmed in Attica, Greece

Greece confirmed two West Nile virus cases in Attica – one in Agia Paraskevi and another in Glyfada – prompting mosquito spraying, red‑zone alerts and public health advice.

3 sources. https://clstr.news/cluster/greece-records-first-west-nile-virus-case-of-2026

### 2026-07-13: First West Nile Virus Case Detected in Lazio, Italy

Italy's Lazio region reported its first 2026 West Nile virus case in a 29‑year‑old from Latina, underscoring effective surveillance as the disease spreads nationwide.

2 sources. https://clstr.news/cluster/first-west-nile-virus-case-detected-in-lazio-italy

### 2026-07-13: West Nile virus cases surge early in US 2026, Arizona epicenter

The 2026 West Nile season hits the US early, with 48 cases—32 in Arizona's Maricopa County—and a first Los Angeles County case, prompting heightened mosquito‑control warnings.

6 sources. https://clstr.news/cluster/west-nile-virus-cases-surge-early-in-us-2026-arizona-epicenter

### 2026-07-10: Italy's Emilia region asks for funds to fight West Nile virus while Calabria reports health service gains

Emilia-Romagna seeks emergency funds to combat West Nile virus spread, while Calabria cites a record rise in health service LEA scores, ending prior commissioner oversight.

2 sources. https://clstr.news/cluster/italys-emilia-region-asks-for-funds-to-fight-west-nile-virus-while-calabria-reports-health-service-g

### 2026-07-10: West Nile virus case confirmed in Alicante, Spain

A 53‑year‑old man in Alicante tested positive for West Nile virus on 1 July; he has been discharged after hospitalisation. Health officials are boosting mosquito surveillance and advising personal protection.

6 sources. https://clstr.news/cluster/spain-records-west-nile-and-crimeancongo-virus-cases

### 2026-07-09: Coarse Salt Recommended to Eliminate Drain Odors and Pests in Brazilian Homes

Brazilian households are advised to use coarse kitchen salt in drains to neutralize odors, inhibit bacteria, and deter pests, offering a cheap, chemical‑free cleaning method.

2 sources. https://clstr.news/cluster/coarse-salt-recommended-to-eliminate-drain-odors-and-pests-in-brazilian-homes

### 2026-07-09: West Nile virus found in mosquito samples across California counties

Mosquitoes in Ventura County and the Coachella Valley tested positive for West Nile virus, prompting health alerts and mosquito‑control measures across the California communities.

2 sources. https://clstr.news/cluster/west-nile-virus-found-in-mosquito-samples-across-california-counties

### 2026-07-09: First human West Nile virus cases confirmed in Texas Denton County and Mississippi Hancock County

Human West Nile virus cases were confirmed this season in Denton County, Texas and Hancock County, Mississippi, prompting health alerts and mosquito precautions.

3 sources. https://clstr.news/cluster/first-human-west-nile-virus-cases-confirmed-in-texas-denton-county-and-mississippi-hancock-county

### 2026-07-09: Greece reports first West Nile virus case of 2026

Greece's health agency reported the first West Nile virus case of 2026 – a senior patient with meningo‑encephalitis likely infected in Agia Paraskevi – and issued mosquito‑control and personal‑protection advice

10 sources. https://clstr.news/cluster/greece-records-first-west-nile-virus-case-of-2026-season

### 2026-07-08: Emilia-Romagna reports early, extensive West Nile virus activity across six provinces

Emilia‑Romagna’s health authority reports early West Nile virus activity in mosquitoes across six provinces, the widest and earliest since 2008, with no human cases yet but heightened risk and preventive advice

5 sources. https://clstr.news/cluster/emilia-romagna-reports-early-extensive-west-nile-virus-activity-across-six-provinces

### 2026-07-07: West Nile virus found in mosquitoes in Seville and Almería, Spain

West Nile virus was detected in mosquitoes in Seville and Almería, prompting heightened surveillance and prevention measures, while doctors in Alicante warn of rising allergic reactions to mosquito bites and ad

3 sources. https://clstr.news/cluster/west-nile-virus-found-in-mosquitoes-in-seville-and-almera-spain

### 2026-07-07: California sees fastest West Nile spread in 20 years, urges mosquito precautions

California health agencies report record early West Nile activity, prompting bite‑prevention advice and a new Wolbachia‑mosquito release program in Contra Costa.

4 sources. https://clstr.news/cluster/california-sees-record-west-nile-surge-as-counties-roll-out-new-mosquito-control-measures

### 2026-07-04: Skopje Clinic Confirms Two West Nile Fever Cases

The University Clinic for Infectious Diseases in Skopje confirmed two West Nile fever cases; both patients are hospitalized and monitored, and authorities urge mosquito‑bite protection as similar regional cases

4 sources. https://clstr.news/cluster/skopje-clinic-confirms-two-west-nile-fever-cases

### 2026-07-04: Macedonia confirms two West Nile virus cases at University Infectious Diseases Clinic

Macedonia’s University Infectious Diseases Clinic confirmed two West Nile virus cases, hospitalising both patients and urging mosquito‑bite prevention as the summer season heightens risk.

4 sources. https://clstr.news/cluster/macedonia-confirms-two-west-nile-virus-cases-at-university-infectious-diseases-clinic

### 2026-07-04: West Nile Virus Cases Confirmed at Skopje Infectious Disease Clinic

Two West Nile virus cases were confirmed at Skopje's infectious disease clinic; patients are hospitalized, and officials urge mosquito‑bite prevention as summer mosquito activity rises.

4 sources. https://clstr.news/cluster/west-nile-virus-cases-confirmed-at-skopje-infectious-disease-clinic

### 2026-07-04: Two West Nile fever cases confirmed in Skopje, Macedonia

Two West Nile fever infections were confirmed at Skopje's University Infectious Diseases Clinic; both patients are hospitalized and officials urge mosquito‑bite protection.

2 sources. https://clstr.news/cluster/two-west-nile-fever-cases-confirmed-in-skopje-macedonia

### 2026-07-02: US CDC warns early and intense West Nile virus season

CDC reports the earliest West Nile season in over 20 years, with 48 cases (38 neuroinvasive) across 23 US states and a surge in Arizona, urging mosquito‑bite prevention.

4 sources. https://clstr.news/cluster/us-cdc-warns-early-and-intense-west-nile-virus-season

### 2026-07-02: West Nile Virus Outbreak Prompts Widespread Mosquito Alerts in Arizona and California

Arizona reports 29 West Nile cases and four deaths, issuing urgent outdoor safety warnings, while California finds infected mosquitoes in ten cities, urging repellents and water removal.

2 sources. https://clstr.news/cluster/west-nile-virus-outbreak-prompts-widespread-mosquito-alerts-in-arizona-and-california

### 2026-07-01: CDC warns early West Nile virus surge across the United States

CDC reports an early, record‑early West Nile virus season with 48 U.S. cases, 38 severe, mainly in Arizona, and urges mosquito‑bite prevention measures.

7 sources. https://clstr.news/cluster/cdc-warns-of-early-severe-west-nile-virus-season-in-us

### 2026-06-29: Almería health authorities deploy ~100 inspectors for West Nile virus mosquito surveillance

Almería deploys about 100 health inspectors and weekly mosquito traps to monitor West Nile virus, while officials urge repellents, long clothing and removal of standing water to prevent infection.

2 sources. https://clstr.news/cluster/almera-health-authorities-deploy-100-inspectors-for-west-nile-virus-mosquito-surveillance

### 2026-06-28: West Nile virus cases surge in US, prompting mosquito warnings from Arizona to California and Minnesota

West Nile virus cases rise across the US, with 25 infections and two deaths in Arizona, positive mosquitoes in California and Minnesota, and new animal detections prompting mosquito control warnings.

5 sources. https://clstr.news/cluster/west-nile-virus-cases-rise-in-nevada-and-arizona

### 2026-06-25: US counties issue West Nile virus mosquito alerts

Lake County and Contra Costa County report the first West Nile‑positive mosquitoes of the year, urging residents to eliminate standing water, use EPA‑approved repellents, and monitor for dead birds to prevent a

2 sources. https://clstr.news/cluster/us-counties-issue-west-nile-virus-mosquito-alerts

### 2026-06-24: Serbia reports zero human West Nile virus cases as surveillance continues

Serbian health officials say no human West Nile virus cases have been recorded as of 22 June 2026, while surveillance continues amid ongoing European transmission.

4 sources. https://clstr.news/cluster/serbia-reports-zero-human-west-nile-virus-cases-as-surveillance-continues

### 2026-06-23: Veneto records first human West Nile case, intensifies mosquito control

Veneto confirmed its first human West Nile case (22 June 2026) and launched heightened mosquito control, free larvicide distribution, and updated blood‑transplant safety measures.

6 sources. https://clstr.news/cluster/first-human-west-nile-virus-case-confirmed-in-veneto-italy

### 2026-06-20: West Nile cases surge in Italy as health officials stress mosquito control

Italy recorded 773 West Nile cases in 2025, a 133 % rise, but strict blood‑donor screening stopped any transmission; officials urge mosquito‑control measures.

10 sources. https://clstr.news/cluster/effective-mosquito-prevention-methods-recommended-for-homes

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