San Antonio's long mosquito season runs from roughly spring through late fall, and during those months the question of health risk is a reasonable one. Most mosquito bites result in nothing more than an itchy welt. But Texas has documented mosquito-borne illness cases every year, and South Texas sits in a geographic position where diseases common in northern Mexico can occasionally show up here too. Understanding what circulates in our region is worth a few minutes.
Quick answer
Yes. Texas mosquitoes can transmit several diseases, with West Nile virus being the most consistently present threat in the San Antonio region. Dengue fever cases have also been reported in South Texas. Protecting yourself means eliminating standing water around your property and reducing the mosquito population in your yard with targeted treatments.
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West Nile Virus: The Consistent Local Threat
West Nile virus is the mosquito-borne disease most reliably present in Texas. The Texas Department of State Health Services reports human West Nile cases across the state every year, with Bexar County and the surrounding region included in most active seasons. The virus circulates between birds and the Culex mosquito species that bites both birds and humans.
Most people infected with West Nile virus have no symptoms or a brief flu-like illness. About one in 150 infected people develops a severe neurological illness, which is more dangerous for older adults and people with weakened immune systems. There is no vaccine or specific treatment, which puts prevention squarely at the front of the approach.
Dengue and Zika in South Texas
Dengue fever is transmitted by the Aedes aegypti mosquito, which is established in South Texas. Locally transmitted dengue cases have been reported along the Texas-Mexico border, and the species that carries it is common in San Antonio. Most dengue infections cause fever, rash, muscle pain, and fatigue. A small percentage develop severe dengue, which can be life-threatening.
Zika made headlines in 2015 and 2016, and the Aedes aegypti mosquito is its primary vector too. Activity has dropped from that peak. The mosquito that carries it, though, hasn't gone anywhere in South Texas. The real concern with Zika is the risk of serious birth defects when a pregnant woman is infected.
The Species in Your Yard
Two mosquito types cause most of the trouble in San Antonio neighborhoods. Culex quinquefasciatus, the southern house mosquito, is the main West Nile vector. It breeds in standing water, bites at dusk and at night, and prefers birds but feeds on humans readily. It's the species most people notice swarming around their yard in the evenings.
Aedes aegypti is the dengue and Zika vector. It's smaller, daytime-biting, and breeds in very small water containers like flower pot saucers, clogged gutters, bottle caps, and birdbaths. You're less likely to notice this one coming, which is part of what makes it an effective disease vector.
- Storm drains, clogged gutters, and low spots that hold rainwater
- Flower pot saucers, plant trays, and birdbaths left unchanged
- Children's toys, buckets, and tarps that collect water
- Pet water dishes and ornamental ponds without circulation
Personal Protection During Peak Season
The CDC recommends EPA-registered insect repellents with DEET, picaridin, or oil of lemon eucalyptus for skin protection. Wearing long sleeves and pants during peak biting hours helps, and wearing light colors makes mosquitoes easier to spot before they bite.
Those are good habits for outdoor activity outside your yard. Inside your yard, the more effective approach is cutting the population down at the source: eliminating standing water and treating the resting and breeding areas that keep the local population fed and producing.
How Yard Treatments Fit In
A professional yard treatment goes after the shaded, humid spots where mosquitoes rest during the day. Hit those, and the numbers drop fast. Applied to dense vegetation, shrub beds, and shaded ground cover, the treatment cuts the resting adult population around your home, and recurring applications through the season hold that reduction as new adults keep emerging from breeding sites nearby.
Bob Jenkins Pest & Lawn Services uses EPA-registered, least-toxic products applied to the spots where mosquitoes actually spend their time. The combination of eliminating standing water and reducing the yard population is the most practical way to lower your family's exposure during San Antonio's long mosquito season.