The 2026 North Texas Mosquito Report

West Nile virus is the most common mosquito-borne illness in the continental United States, and North Texas has been one of its recurring hotspots since the virus reached Texas in 2002. This report compiles publicly reported figures for the four core Dallas–Fort Worth counties from the agencies that track the disease — the Texas Department of State Health Services (DSHS), the U.S. Centers for Disease Control and Prevention (CDC), and county health departments. Every figure below is sourced; the full citation list is at the end of the page.

The 2012 benchmark: the worst West Nile outbreak in Texas history

To understand North Texas and West Nile, you have to start with 2012. That year, Texas recorded 1,868 human cases and 89 deaths statewide — the worst West Nile outbreak in Texas history. The Dallas–Fort Worth metro was the epicenter, accounting for 902 cases, roughly 48% of the entire state total.

Here is how those 902 metro cases broke down across the four core counties:

Dallas County bore the heaviest toll: 19 deaths and a record neuroinvasive disease incidence of 7.3 cases per 100,000 residents— the figure that drove the county to declare a public-health emergency and conduct aerial spraying that summer.

The 2025 season: a county-by-county comparison

The table below compares the four core counties across the three measures that matter most for West Nile risk: confirmed human cases, the number of mosquito samples (“pools”) that tested positive for the virus, and the per-capita case rate that normalizes for each county’s population.

Statewide in 2025, Texas reported 1,284 positive mosquito pools, 125 human cases, and 4 deaths.

Data note: the 2025 county figures are preliminary, drawn from the Texas DSHS Arbovirus Activity Report (Week 50, December 13, 2025). They will be updated when DSHS publishes its finalized annual summary.

The finding: the center of gravity has shifted west

In 2012, Dallas County was the unambiguous epicenter — 396 cases, 19 deaths, and a record per-capita rate. In 2025, that is no longer where the pressure concentrates. Tarrant County led all four core counties in 2025 on every measure:the most human cases (17), the most positive mosquito pools (289), and the highest per-capita rate (~0.79 per 100,000) — more than double Dallas County’s ~0.30.

This is the report’s central, citable finding: the most intense West Nile activity in the metro’s most recent season was centered not in Dallas but to its west, in Tarrant County and communities such as Fort Worth and Arlington. It is worth stating plainly what this does and does not mean: a single season is not a trend, and case counts are sensitive to testing, weather, and reporting. But on the 2025 numbers, the county that carries the metro’s heaviest historical association with West Nile — Dallas — was not the county with the heaviest current burden.

Where the 2026 season stands now

As of the Texas DSHS Arbovirus Activity Report for Week 33 (data through August 22, 2026), the 2026 West Nile season continues to escalate across North Texas. WNV-positive mosquito pools by county so far this season: Dallas 166, Tarrant 142, Denton 38, Collin 19. Three of the four core counties have now reported confirmed human cases. On July 10, 2026, Denton County Public Health reported Denton County’s first human case of the season — a Denton resident, the non-neuroinvasive (West Nile fever) form. On July 30, 2026, Denton County Public Health reported the county’s second human case of the season — a resident of The Colony, who the county said was diagnosed with West Nile Virus Neuroinvasive Disease, the first case Denton County has reported in the neuroinvasive form this year. On July 24, 2026, Tarrant County Public Health confirmed the county’s first human West Nile case of the season — a West Nile Neuroinvasive Disease case, a classification the state’s weekly tables have since corroborated. Neuroinvasive West Nile is the more severe presentation, which can cause neurological symptoms and can be life-threatening. DSHS’s Week 33 report now lists six Tarrant County cases — one West Nile fever and five neuroinvasive — up from two the week before, the largest one-week increase any of the four core counties has posted this season. On August 11, 2026, Dallas County Health and Human Services confirmed the county’s first human case of the season — a Dallas resident in their early 50s, who the county said was diagnosed with West Nile Neuroinvasive Disease. DSHS’s Week 33 table lists a second Dallas County case, also neuroinvasive, bringing the county to two. Collin County has reported no confirmed human West Nile cases as of this update. Tarrant County now accounts for six of the ten human cases across the four core counties in 2026 — echoing the 2025 pattern the report documents above.

Statewide, Texas has now logged 1,224 positive mosquito pools and 42 human cases (10 West Nile fever, 32 neuroinvasive), with no deaths reported. The county pool counts, statewide totals, and any case counts attributed above to DSHS reports are DSHS preliminary weekly figures. The Denton, Tarrant, and Dallas cases attributed to county health departments, and their neuroinvasive or non-neuroinvasive classifications, are county announcements and may differ from the DSHS weekly arbovirus coding. These update through the season; we do not estimate in-season numbers.

Why North Texas is a West Nile hotspot

North Texas combines several conditions that favor the Culex mosquitoes that carry West Nile:

• Blackland Prairie clay soils. The region’s heavy, slow-draining clay holds water at the surface after rain and irrigation, creating the shallow, stagnant pools where Culex larvae develop.
• Engineered stormwater retention ponds.The metro’s master-planned suburbs are dotted with retention and detention ponds that hold standing water through the warm months.
• Creek and lake watersheds. Extensive creek systems and reservoirs across the four counties provide year-round breeding margins and backwater habitat.
• Mild winters and long, hot summers. Relatively mild winters allow Culexmosquitoes to overwinter, and the region’s long, hot summers extend the transmission season well into the fall.

For a season-specific look at how these conditions play out across the metro, see our DFW mosquito season guide and the mosquito control overview.

How to reduce your risk

Public-health guidance from the CDC and local health departments focuses on eliminating breeding sites and reducing exposure. The practical steps for households:

• Drain standing water weekly. Empty and scrub anything that holds water — flowerpot saucers, buckets, toys, tarps, clogged gutters, birdbaths, and pet bowls. Culex can complete their life cycle in as little as a tablespoon of water.
• Treat water that cannot be drained. For ornamental ponds and rain barrels, mosquito-control products containing Bacillus thuringiensis israelensis (Bti) target larvae and are harmless to fish, pets, and wildlife.
• Use EPA-registered repellent. Products with DEET, picaridin, IR3535, or oil of lemon eucalyptus are effective when used as directed.
• Dress and time it. Wear long sleeves and pants and limit outdoor exposure at dawn and dusk, when Culex mosquitoes are most active.
• Keep them out. Repair torn window and door screens and make sure they seal.

Mosquito control by North Texas city

• Mosquito Control in Dallas→
• Mosquito Control in Fort Worth→
• Mosquito Control in Arlington→
• Mosquito Control in Plano→
• Mosquito Control in Frisco→
• Mosquito Control in McKinney→
• Mosquito Control in Garland→
• Mosquito Control in Irving→

Sources

This report compiles figures reported by public-health agencies and credited news coverage. Where a stable primary source is available, it is linked directly.

• Texas Department of State Health Services (DSHS) — Arbovirus Activity Report, Week 50 (December 13, 2025). Source of the 2025 county and statewide figures. DSHS Week 50 report (PDF) · DSHS West Nile hub
• Texas DSHS — Arbovirus Activity Report, Week 33 (week ending August 22, 2026; report dated August 25, 2026). Source of the current 2026 county and statewide figures. DSHS Week 33 report (PDF)
• Denton County Public Health — first 2026 human West Nile case (Denton resident, announced July 10, 2026). Denton Record-Chronicle
• Denton County Public Health — second 2026 human West Nile case, reported as the neuroinvasive form (resident of The Colony, announced July 30, 2026). DCPH news release · Denton Record-Chronicle · KERA News
• Tarrant County Public Health — first 2026 human West Nile case, which the county announced as the neuroinvasive form (July 24, 2026). TCPH news release · KERA News · Fort Worth Report
• Dallas County Health and Human Services — first 2026 human West Nile case, reported as West Nile Neuroinvasive Disease (Dallas resident in their early 50s, announced August 11, 2026). DCHHS news release (PDF) · FOX 4 Dallas-Fort Worth · KERA News
• Texas DSHS — first confirmed 2026 Texas West Nile case (Harris County, May 2026). Source for the 2026 season status. dshs.texas.gov news alert
• CDC Emerging Infectious Diseases — Murray et al., “West Nile Virus, Texas, USA, 2012” (Vol. 19, No. 11, November 2013). Source of the 2012 benchmark figures. CDC EID (journal of record) · PMC mirror
• Texas DSHS — Annual Summaries for Arbovirus Activity in Texas: the state’s year-by-year arbovirus totals, with finalized annual summaries published for 2012–2020. Context for where the 2012 season sits in Texas history. DSHS annual arbovirus summaries
• NPR — “A Warm Winter Helped Fuel West Nile Outbreak In Dallas” (2013), on the 2012 outbreak. npr.org
• KERA News — reporting on the opening of the 2026 North Texas mosquito season in Tarrant County. keranews.org
• U.S. Centers for Disease Control and Prevention (CDC) — West Nile virus national surveillance and prevention guidance. cdc.gov/west-nile-virus
• U.S. Census Bureau — 2025 population estimates, used as the per-capita denominators. census.gov
• County health departments— Dallas County Health and Human Services, Tarrant County Public Health, Denton County Public Health, and Collin County Health Care Services, which conduct local mosquito trapping and report county case data to DSHS.

Pestcura is a nationwide network connecting homeowners to licensed local pest control professionals; we do not perform pest control services. This report is an editorial data compilation for public information and is not medical advice. For health concerns related to West Nile virus, consult a physician or your local health department.