Staff Report
SAN MARCOS — As part of routine surveillance for diseases transmitted by mosquitoes, the Hays County Development Services (HCDS) Mosquito Surveillance Program has received confirmation from the Texas Department of State Health Services (DSHS) that two mosquito trap samples collected in ZIP code 78666 have tested positive for West Nile Virus (WNV).
The positive samples were collected from two separate sites in San Marcos July 7 and these are the first two West Nile Virus-positive mosquito traps reported in Hays County during the 2026 season.
As of July 5, statewide, the DSHS reported 462 positive mosquito traps. At this time, no human cases of WNV have been reported in Hays County.
Mosquitoes are present year-round, but are most active from May through November. Infected mosquitoes can transmit WNV through bites.
Most infected people, or 80%, have no symptoms, while about 20% may develop fever, headache, body aches, rash or other flu-like symptoms. Adults aged 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 WNV 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.
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.
“Hays County is committed to protecting the health and well-being of our residents and we’re staying proactive in monitoring mosquito activity across the county. With traps testing positive for West Nile Virus, it’s important for all of us to take simple steps to stay safe — use insect repellent, wear long sleeves when outdoors and empty any standing water around your home,” said Hays County Judge and Director of Emergency Management Ruben Becerra. “I want to thank our Health Department and Development Services teams for their continued efforts to keep our community informed and protected and we appreciate our residents for doing their part, as well. Together, we can help reduce the risk and keep Hays County safe and healthy.”
For more information regarding mosquito surveillance, visit the Hays County Development Services website or call (512) 393-2150. More information on human risk can be found on the Hays County Health Department's Epidemiology & Disease Prevention website at www.hayscountytx.gov/392/Epidemiology-Disease-Prevention.
