Mosquito Season Breeds West Nile Cases

The first Texas case of West Nile illness in 2025 was confirmed June 24 in a resident of Brazos County, according to public health officials reported last week. The Texas Department of State Health Services (TDSHS) confirmed the resident was diagnosed with West Nile fever.

“Texans should be aware that mosquitoes transmit disease, and some of these illnesses, like West Nile and dengue, can be severe,” said TDSHS Commissioner Dr. Jennifer A. Shuford, MD, MPH. “But taking steps to prevent mosquito bites and eliminating mosquito breeding areas around homes are proactive measures that can reduce the risk of mosquito-borne illness.”

Mosquitoes remain active into November and December in much of Texas. Last year, Texas reported 455 cases of West Nile disease and 56 deaths. Over the last five years (2020-2024), Texas has had 929 West Nile cases and 122 deaths. There were 241 cases of dengue in Texas in 2024, including two locally acquired cases.

Infected mosquitoes transmit West Nile after biting, and although 80% of people exposed to the virus do not get sick, the rest will develop symptoms like fever, nausea, headache, fatigue, and muscle and joint pain. Less than 1% of those exposed will suffer from West Nile neuroinvasive disease, which affects the nervous system and can cause disorientation, neck stiffness, tremors, paralysis, convulsions, and even death.

As of July 1, the U.S. Centers for Disease Control and Prevention (CDC) has confirmed 24 cases of West Nile virus disease this year in 14 states. (The CDC acknowledges cases are probably higher with delayed reporting.) West Nile virus neuroinvasive disease cases were confirmed in 10. Last year, the CDC reported 1,791 cases and 164 deaths from the West Nile virus.

Health officials provided these steps to protect from West Nile and other mosquito-borne illnesses like dengue:

• Wear long sleeves and pants. Create a barrier to mosquito bites by covering up.
• Apply insect repellent. Use an U.S. Environmental Protection Agency-registered repellent such as those containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone.
• Keep mosquitoes out by keeping doors and windows closed and/or installing window screens.
• Remove standing water. Emptying out water that accumulates in toys, tires, trash cans, buckets, clogged rain gutters, and plant pots will deny mosquitoes a place to lay their eggs and reproduce.

Other mosquito breeding prevention tips include:

• Change water in pet dishes daily.
• Rinse and scrub vases and other indoor water containers weekly.
• Change water in wading pools and bird baths several times a week.
• Use mosquito dunks with larvicide for water that can’t be emptied or covered.
• Keep backyard pools and hot tubs properly chlorinated and free of debris.
• Treat front and back door areas of homes with residual insecticides if mosquitoes are in abundance nearby.
• If mosquito problems persist, consider pesticide applications for vegetation around the home.