Arlington Sprays Two Nights for West Nile as Texas Case Count Reaches 46 at Season's Peak

Arlington spent the first two nights of September fogging a residential neighborhood for West Nile virus, as federal surveillance put Texas at 46 human cases this season — the state's highest count heading into the virus's historical peak weeks.

Tarrant County Public Health notified the city that a mosquito trap sample near the intersection of Caliente Drive and Commander Court had tested positive, triggering two nights of targeted ground spraying on Sept. 1 and 2. Crews worked between 9 p.m. and 5 a.m. within a half-mile radius of the trap, applying a water-based permethrin product at ultra-low volume.

No new human case was announced alongside the spraying. The response was aimed at knocking down the infected adult mosquito population before the virus reaches people.

One positive trap, two nights of fog

Arlington traps mosquitoes from May through October and sends samples to the county lab for West Nile and St. Louis encephalitis testing. The city's standing rule is two nights of spraying after three consecutive weeks of positives at the same trap — but officials can move after a single positive when risk factors are present: more than 50 mosquitoes in the trap, a recent human case nearby, scheduled evening outdoor events, or a high infection rate in the sample.

The city did not say which threshold was met, only that the spraying followed county guidance. It is Arlington's second spraying operation of the season, after two nights of fogging near Douglas Court and North Cooper Street in mid-June.

Tarrant County confirmed its first human West Nile case of 2026 on July 24, a neuroinvasive infection — the severe form that can involve neck stiffness, disorientation, tremors and paralysis. At that point the county had already logged 86 positive mosquito pools. The county recorded 17 human cases in 2025 and 28 in 2024, a season that included its most recent West Nile death.

Peak season arrives with 46 Texas cases

The timing is what elevates a routine spray notice into a warning. August and September are historically the worst months for West Nile transmission in Texas, and the CDC's Sept. 1 update showed the state at 46 reported human cases — up from 31 in mid-August. Texas recorded 127 cases in all of 2025. The state's first case this year was a Harris County resident confirmed in May.

State and county counts run ahead of the federal numbers, which lag by one to two weeks, so the true September tally will likely climb as reports catch up.

City officials stress that spraying buys time, not immunity. The city's "Three Ds" guidance remains the core defense: use a DEET-based repellent outdoors, dress in long sleeves and pants at dawn and dusk, and drain standing water — flowerpot saucers, clogged gutters, old tires, birdbaths — where mosquitoes can complete a breeding cycle in as little as three or four days. Our peak-season protection guide covers the full checklist.

The permethrin formulation used overnight breaks down quickly with little residual effect, and the EPA has determined it does not pose an unreasonable risk when applied as directed. Residents with asthma or chemical sensitivity can reduce exposure by staying indoors during the nighttime application window. Arlington residents can report standing water or heavy mosquito activity through the city's Action Center at 817-459-6777 or the Ask Arlington app.