The Texas Department of State Health Services (DSHS) confirmed the state’s first human case of West Nile virus illness for the 2026 season on May 19. The diagnosis involves a resident of Harris County who contracted West Nile neuroinvasive disease, the most severe neurological manifestation of the virus.
West Nile virus is primarily transmitted through the bite of infected mosquitoes and amplifies across Texas during the warmer months. While roughly 80% of individuals infected with the virus never display symptoms, less than 1% contract the neuroinvasive form, which can lead to serious neurological complications such as tremors, convulsions, paralysis, or death.
According to tracking records maintained by state health authorities, Texas has seen a total of 976 West Nile cases and 106 associated fatalities over the last five years, with provisional figures showing a peak of 57 deaths in 2024 before dropping to 9 fatalities in 2025.
DSHS Commissioner Dr. Jennifer A. Shuford said that mosquito-borne illnesses represent a persistent seasonal reality for Texans. She said that active precaution remains the primary tool for reducing insect populations, urging residents to systematically eliminate standing water sources around their homes — such as in flowerpots, buckets, clogged rain gutters, and toys—where mosquitoes frequently lay eggs.
“West Nile and other mosquito-borne illnesses are a fact of life in Texas in the warmer months, and all Texans should take precautions against mosquito bites to stay safe and healthy,” Shuford said.
State health guidelines also recommend securing window screens, utilizing air conditioning, wearing loose-fitting, long-sleeved clothing during peak mosquito activity hours, and applying EPA-approved repellents containing DEET or picaridin.
The onset of the seasonal West Nile cycle coincides with a broader push by health officials to counter other mosquito-borne threats, including dengue, chikungunya, and Zika. DSHS reports indicate that global cases of dengue and chikungunya have risen sharply in recent years.
While the vast majority of these infections in Texas remain associated with international travel to tropical climates, health authorities have documented a few locally acquired dengue cases in southern Texas over recent cycles. Approximately 25% of symptomatic dengue patients endure severe joint pain and fatigue, and the agency warned that up to one in 20 symptomatic individuals can progress to a severe, potentially fatal form of the disease if left untreated.
State epidemiologists added that because infected travelers can inadvertently seed local mosquito populations upon returning home, rigorous prevention measures must be maintained both abroad and domestically. While a specialized vaccine is commercially available for travelers entering regions where chikungunya is endemic, there is currently no vaccine option to protect against West Nile virus.