Hays County Reports First Human West Nile Virus Case of 2025

The Hays County Health Department has reported its first positive case of West Nile virus in a human this year. It has not reported any positive mosquito pools in 2025.

The department is withholding details about the person who tested positive with the mosquito-borne illness including age, gender and where the person lives for privacy reasons. West Nile virus is contracted after an infected mosquito bites a person.

Hays County health officials said the key to preventing West Nile virus is to minimize the number of mosquitos where people live. It is putting down mosquito traps that encourage females about to lay eggs to go into the trap and has an online map of where it has been tracking mosquitos.

This is the second positive West Nile virus in a human in Central Texas. Earlier in July, Williamson County reported a case in the southern part of that county. It also has not reported any positive mosquito pools this year.

Travis County has not had a human case yet this year, but has had mosquito pools test positive in the 78702, 78723 and 78741 ZIP codes. Austin Public Health has increased surveillance in those areas and has posted notices about the presence of the illness.

With the early July rains and flooding, health officials in the area have been predicting the possibility of West Nile viruses in humans and mosquitos.

"We’re in the midst of mosquito season this year, and this massive rainfall will raise the risk of mosquito-borne diseases in our community," Austin Public Health Environmental Health Services Division Chief Marcel Elizondo said this month.

Last year, one person in Travis County died from the virus. The last death in Central Texas previously was in 2016 in Bastrop County.

In 2024, Texas had 455 cases of West Nile and 56 deaths, according to the Texas Department of State Health Services. As of Saturday, Texas has found 272 positive mosquito pools and nine cases in humans this year.

What are the symptoms of West Nile virus?

"Fortunately, most people who contract West Nile virus never develop symptoms, and the risk of getting seriously ill is very low. The best protection is to prevent getting bitten," said Jason Fritz, integrated vector management program lead in Williamson County.

About 80% of people who contract West Nile virus have no symptoms. Most people who do develop symptoms have fever, headaches, stiff necks, joint pain, body aches, swollen lymph glands, vomiting, diarrhea or a rash. A blood test or a spinal fluid sample can confirm the cause.

You should contact your doctor or go to an emergency room if you are having symptoms, Fritz said.

How can you protect yourself from West Nile virus?

Remember the four D's:

• Drain standing water. Empty buckets, toys, tires, pools, plant pots and clogged gutters. Mosquitoes breed in standing water and need as little as 1 teaspoon to lay their eggs.
• Dusk and dawn. The mosquito that spreads West Nile virus is most active at dusk and dawn.
• Dress: Wear light-colored, loose-fitting clothing and long pants and long sleeves when you are outside. Clothing is available with built-in mosquito protection.
• DEET: Apply insect repellant that has DEET in it. Use it on both skin and clothing.