The Dallas County health department is reporting the state’s first human case of West Nile virus in 2023.
Officials with Dallas County Health and Human Services said in a news release Monday that a Dallas man was diagnosed with West Nile Neuroinvasive Disease, which can cause fever, headache and muscle aches, or, in severe cases, neurologic complications like brain inflammation.
Last year the county recordedthree human cases and one death related to West Nile virus. In 2021 there were 28 casesand three deaths.
Mosquitoes testing positive for the West Nile virus are on the rise across North Texas, and therising heat could make the problem worse.
Dallas, Fort Worth, Denton, Plano and Arlington counties have reported infected mosquitoes in their traps.
DCHHS public information officer Christian Grisales said over the last few years there was less testing and outdoor activity because of the pandemic, which kept case numbers lower.
“It's likely we're seeing the trends going up,” Grisales said. “The cases are going up for mosquito traps, positive pools. So, whenever that happens, there is a risk [for mosquitoes that] for people [to get] to be a victim of mosquito bites.”
DCHHS emphasizes the importance of preventive measures like the “four Ds” — wearing insect repellent with DEET; dressing in long, loose and light clothing; draining or treating standing water; and limiting outdoor activity from dusk to dawn.
The West Nile virus was first detected in Texas in 2002.
Baylor College of Medicine assistant professor Sarah Gunter said that while some years are worse than others for West Nile, a warming climate can increase the spread of the disease.
“As temperatures get hotter, it's definitely going to affect mosquito populations,” Gunter said. “It has the potential to make disease transmission more common.”
Gunter said the heat could increase the length of mosquito season, making them come out sooner and stay around longer.
And it’s not just mosquitoes: A warming climate is also driving up activity of other disease-carrying insects such as ticks, kissing bugs and sand flies.
“For our other vectors, we're seeing an expansion of where these vectors are,” Gunter said. “So, like for our tick borne diseases, we're seeing ticks in areas that we historically haven't seen them.”
The Centers for Disease Control and Prevention says there are no vaccines to prevent or medication specifically to treat the West Nile virus in humans but most people that are infected do not feel sick.
Roughly one in five people infected with West Nile will be symptomatic, and roughly one out of 150 will develop serious illness that could be fatal.