West Nile Virus 2026: Early Season Detected in Texas, Louisiana & California | Virus Watcher
10 Épidémie ActivesWest Nile Virus is showing early 2026 season activity across multiple states before the typical transmission season begins. Positive mosquito pools have been confirmed in Texas (San Antonio, Frisco), Louisiana (New Orleans), and six California counties. Human cases have already been confirmed in Colorado. Peak transmission season runs July through September — and an above-average season is projected for 2026. Most infections are mild or asymptomatic, but about 1 in 150 infected people develop severe, potentially fatal brain inflammation.
Qu'est-ce que West Nile Virus?
West Nile Virus arrived in the U.S. in 1999 and has since become the leading mosquito-borne disease in the country. It's transmitted by Culex mosquitoes that bite infected birds. While 80% of infected people have no symptoms, severe cases can cause encephalitis or meningitis with long-term neurological effects. Age over 60 significantly increases risk of severe disease.
SymptĂ´mes
- Mild (West Nile fever): Fever, headache, body aches, joint pain, vomiting, diarrhea, rash
- Severe: High fever, severe headache, stiff neck, disorientation, tremors, seizures
- Neurological: Muscle weakness, vision loss, paralysis, coma
- Long-term effects: Fatigue, memory problems, muscle weakness (can persist months/years)
Transmission
Transmitted through bites of infected Culex mosquitoes. Rarely through blood transfusion, organ transplant, mother to fetus, or breastfeeding. NOT spread person-to-person through casual contact.
Période de Contagiosité : Not contagious person-to-person; can be in blood of infected person during illness
Prévention
- Use EPA-registered insect repellents (DEET, picaridin, IR3535, oil of lemon eucalyptus)
- Wear long sleeves and pants at dawn/dusk when mosquitoes most active
- Install/repair window and door screens
- Use air conditioning when possible
- Eliminate standing water (buckets, flower pots, bird baths, gutters)
- Change water in pet bowls, birdbaths weekly
- Treat or drain swimming pools, fountains
- Community mosquito control programs (spraying, larvicides)
- Avoid outdoor activities at dawn/dusk during peak season
Live West Nile Virus Global Case Map
5 countries with reported activity. Updated from real-time surveillance data.
United States — State Detail
1 state with reported activity. Click a state for detailed surveillance.
Épidémies Actives et Cas Récents
Renseignements en temps réel issus de la surveillance sanitaire mondiale et de la surveillance par IA
Sources de données : BEACON, ProMED, OMS, CDC et plus de 50 agences nationales de santé
✓ Données en direct mises à jour en temps réel depuis les sources de santé mondiales
🚨 Arizona mom warns of mosquito dangers after son contracts West Nile
An Arizona mother is warning the public about mosquito dangers after her son contracted West Nile Virus. This highlights an active and ongoing public health threat requiring immediate preventative action from residents in the affected area.
West Nile Virus Hits Anguilla First Local Case
Anguilla confirmed its first autochthonous (locally acquired) human case of West Nile virus in March 2026, while evidence of viral circulation in birds, horses, and mosquitoes has existed across Caribbean territories since the early 2000s.
Source: BEACON - View Full Report
West Nile Virus Arrives Early in Italy
A single laboratory-confirmed West Nile virus case has been identified in Oristano, Sardinia, in mid-May 2026 — earlier in the season than historically typical — in an elderly individual who has since recovered. While the current situation is limited to one confirmed case with no fatalities or evidence of wider spread, the early detection is notable given Italy's sustained and geographically expanding WNV endemicity.
Source: BEACON - View Full Report
West Nile virus, India
This event envelope contains reports on WNV cases, clusters and outbreaks in India.
Source: BEACON - View Full Report
Second bird tests positive for West Nile virus in Ventura County
Matthew Rodriguez is a digital producer for CBS Los Angeles. He's previously reported for local outlets like the Argonaut and Pasadena Weekly. Matt typically covers breaking news and crime.
For the second time this year, public health staff said a bird in Ventura County tested positive for West Nile virus.
The Ventura County Environmental Health Division announced the discovery on Tuesday after receiving confirmation from the California Department of Public Health. County staff said they expect
đź“° 21 news sources reporting on this story.
Wilmette becomes latest Chicago suburb to collect West Nile-positive mosquitoes this year
Adam Harrington is a digital producer at CBS Chicago, where he first arrived in January 2006.
The North Shore suburb of Wilmette this week became the latest Chicago-area municipality to discover mosquitoes carrying the West Nile virus this year.
The North Shore Mosquito Abatement District reported that a batch of mosquitoes collected in a trap in Wilmette Sunday tested positive for West Nile the following day.
In the north suburbs under the jurisdiction of the North Shore Mosquito Abatement Di
đź“° 21 news sources reporting on this story.
West Nile Virus Neuroinvasive Case Hits Texas, Early Season
This envelope collects reports on West Nile virus (WNV) disease in the US.
Source: BEACON - View Full Report
Man issues warning after contracting dangerous disease while doing yard work: 'Make sure that people are aware'
In Canada's warmer-than-usual summer in 2025, some homeowners stayed busy with outdoor tasks. However, this also provided mosquitoes with an extended period to prey on unsuspecting humans. Ontario resident René van den Berg spent 11 days in the hospital after contracting the West Nile virus (WNV) i... Source: Yahoo - Read Full Article
'Avoid mosquito bites': 9th human case of West Nile virus identified this season, health officials say - The Boston Globe
"This case is a reminder that WNV infections can occur even in the fall, and we should remain vigilant," said Public Health Commissioner Robbie Goldstein in a statement. "We are now past the peak season for West Nile virus in Massachusetts, but some risk will continue until the first hard frost." W... Source: The Boston Globe - Read Full Article
Denton County reports third human case of West Nile virus this year, officials say
The Denton County Public Health department on Thursday reported the third human case of West Nile virus in the county, according to a news release. The person who contracted West Nile virus lives in Denton, but the county declined to release any information about the patient. To respect patient co... Source: The Dallas Morning News - Read Full Article
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Ressources Expertes et Références
Informations fiables provenant des principales organisations de santé
CDC
Directives officielles des Centers for Disease Control and Prevention des États-Unis
Voir les Ressources du CDC →WHO
Surveillance mondiale des maladies et directives de l'Organisation Mondiale de la Santé
Voir les Ressources de l'OMS →Contenu Révisé Médicalement
Les informations sur les maladies sur Virus Watcher sont révisées par notre Épidémiologiste en Chef, ancien analyste principal du CDC pour les prévisions FluSight. Les données épidémiques sont agrégées à partir de sources vérifiées notamment BEACON, ProMED, OMS, CDC et plus de 50 agences nationales de santé. Ces informations sont à des fins éducatives et ne doivent pas remplacer les conseils médicaux professionnels.
Dernière révision : 2026-06-29
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