West Nile Virus Season Begins in Tarrant County: First Positive Mosquitoes Detected in Fort Worth and Grand Prairie

Tarrant County Public Health officials have confirmed the first positive mosquito samples for West Nile Virus this year, marking the official start of the 2026 West Nile season in North Texas. The infected mosquitoes were collected in Fort Worth and Grand Prairie during routine surveillance operations.

As of May 14, the county's North Texas Regional Laboratory has tested 314 mosquito samples. While no human cases have been reported in 2026, health officials emphasize that the detection serves as an early warning for residents to take precautions.

The timing aligns closely with last year's season, which also began in early May. In 2025, Texas recorded 127 human cases of West Nile Virus, with 2,076 cases reported nationwide. The virus has been endemic in Texas since 2002, with transmission typically increasing from May through October as warmer temperatures extend mosquito activity into fall.

Heightened Surveillance for World Cup

The announcement comes as Tarrant County intensifies mosquito surveillance ahead of the World Cup kickoff in June. Sabrina Vidaurri, associate director of health protection and response at Tarrant County Public Health, briefed county commissioners on May 12 about expanded monitoring efforts.

The department tests mosquito samples for both West Nile Virus and St. Louis encephalitis, coordinating abatement programs across 36 cities within the county. Last year, Tarrant County implemented heavy larvicide treatments to target mosquito larvae before they mature.

"The best way to protect yourself from mosquitos is to reduce the breeding cycle," Vidaurri told commissioners. The public health department has also distributed $20,000 worth of mosquito dunks to participating cities for standing water treatment.

Understanding the Risk

According to the Centers for Disease Control and Prevention, approximately one in five people infected with West Nile Virus develop symptoms, which include fever, body aches, headaches, and joint pain. In severe cases, known as neuroinvasive disease, symptoms can include disorientation, muscle weakness, tremors, paralysis, and potentially death.

No vaccines or specific treatments currently exist for West Nile Virus in humans, making prevention the primary defense.

Protection Recommendations

Tarrant County Public Health recommends residents take the following steps:

• Apply EPA-approved insect repellent when outdoors
• Wear loose-fitting, long-sleeved clothing and pants
• Eliminate standing water around homes and treat with larvicides
• Limit outdoor activity during peak mosquito hours at dawn and dusk

The last West Nile Virus death in Tarrant County occurred in 2024, when the county reported 28 human cases resulting in 24 hospitalizations. Health officials continue to monitor the situation as temperatures rise and mosquito populations grow.