San Antonio and the broader South Texas region are facing an elevated risk of dengue fever this summer, driven by a deadly combination: a record mosquito season, confirmed positive Aedes mosquito activity in Bexar County, and a flood of international visitors from dengue-endemic nations arriving for the 2026 FIFA World Cup. Dengue — a mosquito-borne viral illness — caused a record-breaking global surge in 2024 and 2025, and public health experts warn the conditions in South Texas this summer could allow imported cases to spark local transmission.
The CDC's Health Alert Network has maintained an ongoing advisory about elevated dengue risk in the United States, noting that dengue transmission remains high throughout the Americas. In 2024, Puerto Rico recorded 6,291 dengue cases — more than 52% requiring hospitalization — while more than 1,000 travel-associated dengue cases were reported in Florida alone. With Aedes aegypti mosquitoes now established across Texas, including in Bexar County, every viremic traveler arriving from Mexico, Brazil, or the Caribbean is a potential bridge between international outbreaks and local transmission.
The World Cup's Role in Elevating South Texas Disease Risk This Summer
The 2026 FIFA World Cup is bringing fans from some of the world's highest dengue-burden countries directly into Houston and San Antonio. Brazil — which recorded millions of dengue cases in 2024 — has one of the tournament's largest international fan contingents. Mexico, a co-host nation with active dengue transmission, borders San Antonio directly. Colombia, another tournament participant with high endemic dengue activity, is also sending large fan groups to Texas.
The key mechanism of concern is called "viremic travelers" — people carrying an active dengue infection but not yet symptomatic. If a local Aedes aegypti mosquito bites such a person and then bites an uninfected resident, dengue can establish local transmission. The Texas Department of State Health Services has confirmed Bexar County as having Aedes aegypti populations capable of carrying dengue, Zika, and chikungunya.
Symptoms to Watch and How to Protect Your Family This Summer
Dengue fever typically begins 4 to 10 days after a mosquito bite. Symptoms include a sudden high fever (often reaching 104°F), severe headache, pain behind the eyes, joint and muscle pain, nausea, vomiting, and a rash. Most people recover within a week, but a small percentage develop severe dengue — also called dengue hemorrhagic fever — which can cause internal bleeding, organ failure, and death. There is no specific antiviral treatment for dengue. Management is supportive: fluids, rest, and pain control using acetaminophen, not ibuprofen or aspirin.
The Aedes aegypti mosquito — dengue's primary vector — bites during the day, unlike the dusk-and-dawn Culex mosquito that carries West Nile virus. Standard evening mosquito precautions are not sufficient protection. Residents and visitors in South Texas should apply EPA-registered repellents (DEET, picaridin, or oil of lemon eucalyptus) throughout the day, wear long sleeves and pants during outdoor activities, eliminate standing water around the home weekly, and ensure that window and door screens are intact.
Despite the documented arrival of dengue-endemic visitors and established vector populations in Bexar County, public messaging about dengue — as opposed to West Nile — remains limited in local health department communications. This gap between the known risk and the public information provided to residents represents a missed opportunity to prevent an entirely preventable outbreak.
