West Nile Found in Dallas Mosquitoes

Dallas County Health and Human Services said on May 18 that three new mosquito pools tested positive for West Nile virus in Dallas County. The county’s West Nile Watch bulletin listed one new positive pool in Dallas ZIP code 75244 and two new pools in Farmers Branch ZIP code 75234. The detections add to earlier 2026 bulletins in other Dallas County communities and mark the latest evidence of West Nile activity as mosquito season begins. City and county agencies are urging residents to remove standing water, use insect repellent and monitor official spray notices. ### Where were the latest positive mosquito pools found? The May 18 bulletin from Dallas County Health and Human Services identified Dallas 75244 and Farmers Branch 75234 as the locations of the latest positive mosquito pools. The county said the total for that update was three new pools. Dallas County’s West Nile Watch page says the agency posts ZIP codes where mosquitoes have tested positive and offers residents a way to request mosquito service. The county says people experiencing a mosquito problem can call 214-819-2115 or submit a service request online. ### Does a positive mosquito pool mean people are infected? Texas health officials say a positive mosquito pool shows that infected mosquitoes are present in the area, not that a human case has been confirmed. The Texas Department of State Health Services says West Nile virus is spread mainly through the bite of an infected mosquito. The state health department says about 80% of infected people do not develop illness. Texas DSHS says about 20% develop a milder illness often called West Nile fever, while about one in 150 infected people develops the more severe neuroinvasive form of the disease. ### What are Dallas officials telling residents to do now? The City of Dallas mosquito-control page tells residents to follow the “Four Ds”: drain standing water, limit outdoor activity at dusk and dawn, dress in long and light-colored clothing, and use EPA-approved repellents such as DEET. The city page lists common standing-water sources including birdbaths, pet dishes, potted plants, clogged gutters, toys, old tires and untreated pools. Dallas County Health and Human Services says surveillance and testing continue across the county during mosquito season. The county’s West Nile Watch page says residents can check whether mosquitoes have tested positive in their ZIP code. ### Will the city spray after a positive West Nile test? A City of Dallas mosquito abatement memo dated May 9, 2025, says a mosquito trap that tests positive for West Nile virus activates spraying within a half-mile radius of the trap location. The memo says spraying can begin within 24 hours of confirmation and that the city issues a public notice by 4 p.m. for spraying that starts no earlier than 9 p.m. The same city memo says each location is sprayed for two consecutive nights and that positive trap sites are re-tested within five business days. The city says it uses EPA-approved, water-based products in truck-mounted ground spraying. ### How does Dallas track mosquito activity? The City of Dallas says Code Compliance monitors and tests mosquitoes weekly during peak season and works on larvicide treatment, standing-water reduction and responses to resident complaints. A city mosquito-prevention page says mosquitoes can complete their life cycle from egg to adult in seven to 10 days, which is why officials focus on removing water sources quickly. Dallas County’s public health pages and the City of Dallas mosquito-control pages are the main public sources for updates. The city also says residents can report mosquito issues through 311, while county health officials maintain the West Nile Watch tracker and mosquito-service request line. The City of Dallas says mosquito season runs from May 1 through Oct. 31, and its mosquito-control page directs residents to current spray notices and seasonal sign-ups for the ground-spray opt-out list. Dallas County Health and Human Services says West Nile Watch updates will continue as new mosquito pools are tested and reported.