West Nile virus is a real, recurring public health threat in North Texas — not a distant news story. Tarrant and Dallas counties see confirmed human cases every summer, and the virus circulates in local mosquito populations from June through October. Knowing what symptoms to watch for, when to seek care, and who faces the highest risk can genuinely save a life. Here’s what every DFW resident should understand before mosquito season peaks.
Most People Who Get Infected Feel Nothing
This is the most important fact to understand about West Nile: roughly 80% of people infected with the virus never develop any symptoms. The immune system clears it quietly, and the person never knows they were infected. This is why the virus can circulate widely in a community without setting off immediate alarm bells among residents.
But that silent majority doesn’t mean the 20% who do develop symptoms have nothing to worry about. And for a small but significant fraction of infections, the consequences are severe.
West Nile Fever: The Milder Form
About 1 in 5 infected people develop what’s called West Nile fever, also referred to as West Nile non-neuroinvasive disease. Symptoms typically appear 2–14 days after the mosquito bite and can include:
- Fever (often the defining symptom)
- Headache, sometimes severe
- Body aches and joint pain
- Fatigue and general malaise
- Nausea, vomiting, or diarrhea in some cases
- A flat, blotchy rash on the trunk, in about half of fever cases
West Nile fever usually resolves on its own within a few days to a week. However, significant fatigue can persist for weeks or even months after the acute illness clears — a phenomenon doctors sometimes call post-West Nile syndrome. If you develop fever and significant headache after spending time outdoors during mosquito season, it’s worth mentioning to your doctor that West Nile is active in your area.
West Nile Neuroinvasive Disease: The Severe Form
About 1 in 150 people infected with West Nile virus develops the neuroinvasive form, where the virus crosses into the central nervous system. This is the form that kills and disables, and it is not rare in raw numbers when you consider how many DFW residents are exposed during a high-pressure season. Neuroinvasive disease takes three main forms:
- West Nile meningitis: Inflammation of the membranes surrounding the brain and spinal cord. Symptoms include severe headache, high fever, stiff neck, and sensitivity to light. Usually survivable but requires hospitalization.
- West Nile encephalitis: Inflammation of the brain itself. Symptoms include confusion, disorientation, altered consciousness, seizures, and in severe cases coma. This is the most dangerous form and carries real mortality risk, particularly in older adults.
- West Nile poliomyelitis (acute flaccid paralysis): Sudden muscle weakness or paralysis, often asymmetric, caused by damage to motor neurons in the spinal cord. This form can result in permanent disability.
Who Faces the Highest Risk of Severe Disease
Two factors drive severe outcome risk more than any other:
- Age: Adults over 60 are significantly more likely to develop neuroinvasive disease and to die from it if infected. The risk increases sharply with each decade after 50. Older adults in North Texas should treat mosquito bites during season with appropriate seriousness.
- Immune compromise: People with diabetes, kidney disease, cancer, organ transplants, or HIV have substantially elevated risk of severe outcomes. These individuals should be especially aggressive about personal protection and professional mosquito control on their property.
Healthy adults and children under 50 can still develop neuroinvasive disease, but the odds are meaningfully lower. There are no antiviral medications approved for West Nile virus — treatment is supportive, meaning hospital care manages symptoms while the immune system fights the infection. This is why prevention is not optional for high-risk individuals.
When to Seek Medical Care
If you or a family member develop the following during mosquito season in North Texas, go to an emergency room — do not wait for a scheduled appointment:
- High fever combined with severe headache and stiff neck
- Confusion, disorientation, or altered consciousness
- New muscle weakness or difficulty moving a limb
- Seizures
Tell the emergency team you’ve been potentially exposed to mosquitoes and that West Nile is circulating in your county. West Nile encephalitis requires supportive inpatient care, and early recognition improves outcomes.
Protection Is the Only Defense
There is no human West Nile vaccine. There are no approved antivirals. The only way to avoid West Nile infection is to avoid being bitten by an infected Culex mosquito. That means personal repellent when outdoors, avoiding peak mosquito hours at dawn and dusk, ensuring window and door screens are intact, and most importantly, reducing the mosquito population on your property through professional mosquito control.
If you haven’t looked at what your neighborhood’s specific risk profile looks like, read our breakdown of West Nile virus risk by neighborhood in North Texas. Knowing your area’s history with virus-positive mosquito pools helps you make informed decisions about how aggressively to protect your household.
Hamann has protected Arlington families from mosquitoes since 2006. We take West Nile seriously because we live and work in the same communities our customers do. Professional treatment is the most effective household-level action you can take.
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