Dallas County health officials have detected West Nile virus in local mosquito samples, prompting scheduled aerial and ground spraying in parts of far North Dallas starting Saturday night.
City Councilwoman Cara Mendelsohn announced the control measures on Friday, noting positive samples in Council District 12. Spraying is planned between 9 p.m. and 5 a.m. on July 11–12, weather permitting, in an area bounded by Rosemeade Parkway to the north, Kelly Boulevard to the west, Marsh Lane to the east, and Timberglen Road to the south.
Mosquito samples in Dallas have tested positive for the West Nile Virus. Weather permitting, the area(s) described below are scheduled for mosquito control spraying between 9 p.m. and 5 a.m. each night from Saturday, July 11 to Sunday, July 12.
Control Area: The area to be…
— Cara Mendelsohn 🟦 (@caraathome) July 10, 2026
The City of Dallas and Dallas County Health and Human Services (DCHHS) continue routine mosquito surveillance and control throughout the season. Positive mosquito pools trigger targeted interventions to reduce the risk to residents.
2025 Season Recap in Dallas County
In 2025, Dallas County reported 37 human West Nile virus cases and three deaths, according to DCHHS data. Statewide in Texas, there were 1,284 positive mosquito pools and 128 human cases with four deaths.
Current 2026 Activity
As of early July 2026, Texas has already recorded positive mosquito pools and a small number of human cases, primarily in the Houston area. Dallas County officials are actively monitoring and responding to early detections this season. No human cases have been publicly reported yet in Dallas County for 2026, but surveillance is ongoing.
National Context
West Nile virus is the leading cause of mosquito-borne disease in the continental United States. From 1999 through 2025, more than 59,000 cases were reported nationally, with roughly 3,300 deaths. In a typical year, the U.S. sees approximately 2,000 cases and about 100–200 deaths, mostly among older adults or those with weakened immune systems. Neuroinvasive cases (the severe form affecting the brain and spinal cord) carry the highest risk.
Prevalence in Texas
Texas consistently ranks among the states with the highest West Nile activity due to its warm climate and large mosquito populations. The virus is most prevalent in the South and Central U.S., with notable hotspots in California, Colorado, Texas, Illinois, and Louisiana in recent years.
In Texas, activity often peaks from June through September.
Symptoms
Approximately 80% of infected people show no symptoms. About 20% develop West Nile fever, with symptoms including fever, headache, body aches, joint pain, vomiting, diarrhea, or rash. Less than 1% develop severe neuroinvasive disease, which can cause encephalitis, meningitis, muscle weakness, paralysis, or coma. Older adults and people with certain medical conditions face higher risk of severe illness. There is no specific treatment or vaccine for humans.
Prevention
Health officials recommend the “4 Ds”:
- DEET: Use insect repellent containing DEET, picaridin, or oil of lemon eucalyptus.
- DRESS: Wear long sleeves, long pants, and light-colored clothing.
- DRAIN: Eliminate standing water around homes where mosquitoes breed.
- DUSK to DAWN: Limit outdoor activity when mosquitoes are most active.
Dallas County urges residents to check their yards weekly for standing water in flowerpots, buckets, birdbaths, and gutters.
