Staff Report
SAN MARCOS — Hays County Development Services (HCDS) Mosquito Surveillance Program has received confirmation from the Texas Department of State Health Services (DSHS) that mosquito trap samples collected in the 78666 and 78610 ZIP codes have tested positive for West Nile Virus (WNV).
The San Marcos positive sample was collected from a site July 28 and the one in Buda was collected July 30, marking the fifth West Nile Virus-positive mosquito pool reported by Hays County during the 2026 season. Statewide, the Texas DSHS reported 905 positive mosquito pools in 2026. At this time, no human cases of West Nile Virus have been reported in Hays County.
“With summer at its peak, it is that time of year when people and mosquitoes tend to interact more. Findings this week serve as a reminder that people should take steps to protect themselves while outside by taking simple measures to reduce the risk of mosquito bites,” said Nick VandenBroek, environmental health specialist II. “Wearing lightly colored and loose-fitted long-sleeved shirts and pants, applying EPA-approved insect repellent and draining any unwanted standing water around your homes are simple ways to reduce the risk of possible mosquito bites while enjoying the summer.”
HCDS conducts mosquito surveillance from May through November to monitor mosquito populations and mosquito-borne diseases. Mosquitoes are collected using standardized traps and then sent to the Texas DSHS for identification and arboviral testing. This surveillance helps HCDS track mosquito activity, identify breeding areas and guide prevention and control efforts.
Mosquitoes are present year-round, but are most active from May through November. Infected mosquitoes can transmit West Nile Virus through bites. Most infected people — 80% — have no symptoms, while about 20% may develop fever, headache, body aches, rash or other flu-like symptoms. Adults ages 50 and older and people with weakened immune systems are at higher risk for severe illness. Anyone experiencing these symptoms should seek medical attention.
There is currently no treatment for West Nile Virus.
The best way to prevent WNV is to reduce mosquito populations where people live, work, and play. Residents can reduce their risk of mosquito bites and West Nile Virus infection by following the three Ds: Defend, Dress and Drain.
• DEFEND: Whenever outside, use EPA-approved repellents and always follow label instructions.
• DRESS: Wear long, loose and light-colored clothing outside.
• DRAIN: Drain or treat all standing water in and around the home or workplace where mosquitoes could lay eggs.
“Protecting the health and safety of our residents is one of Hays County's highest priorities,” said Hays County Judge and Director of Emergency Management Ruben Becerra. “While we have not had any reported human cases of West Nile Virus this year, this positive mosquito sample in another part of Hays County is an important reminder that prevention starts at home. I encourage everyone to take simple precautions like using insect repellent, wearing protective clothing and eliminating standing water around their property. By working together, we can help reduce the risk of mosquito-borne illness and keep our communities healthy.”
For more information regarding mosquito surveillance, visit the Hays County Development Services website at www.hayscountytx.gov/493/Mosquito-Surveillance-Program or call (512) 393-2150. Visit the Centers for Disease Control website at www.cdc.gov/west-nile-virus/index.html for more information on the West Nile Virus.
