West Nile virus cases on the rise: How to spot the first symptoms of the infection before it gets serious

It starts like a summer itch. You swat away a mosquito, maybe curse the humidity, then carry on. But what if that bite is more than a nuisance? What if it’s carrying something far more dangerous?

As temperatures climb and mosquito season hits full swing, West Nile virus (WNV) is making headlines again. Across several US states, public health officials are reporting a spike in confirmed West Nile infections, and the numbers are creeping up faster than usual this year.
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The Centers for Disease Control and Prevention (CDC) first confirmed a case of West Nile virus in June, involving a patient from Southern Illinois who was hospitalized with serious complications. A second case was reported in Lake County on July 16, where a resident in their 70s fell ill earlier in the month, marking another confirmed infection during this year’s mosquito season.

So, what’s going on? And more importantly how can you tell the difference between a bug bite and something more dangerous?

West Nile virus is a mosquito-borne illness that spreads when an infected mosquito bites you. Birds are the virus’s preferred host, but mosquitos are the ones doing all the dirty work—biting infected birds and then passing the virus to humans.

Most cases happen during the warmest months, especially July through September. And while the majority of people infected with the virus don’t show any symptoms at all, a small percentage get very sick and some of those cases can turn fatal.

First symptoms of West Nile virus
Here’s where things get tricky. About 8 out of 10 people infected with WNV never feel a thing. But the remaining 20%? They’re hit with something called West Nile fever—and it’s not pretty.

The first signs usually show up 2 to 14 days after a mosquito bite, and can include:

• Fever (mild to high)
• Headache
• Fatigue or feeling “off”
• Body aches and joint pain
• Skin rash (sometimes)
• Swollen lymph nodes
• Eye pain or light sensitivity

Sounds like the flu, right? Or COVID. Or just a really bad Monday. That’s what makes early detection so tricky, it hides in plain sight.

If you’re otherwise healthy, you’ll likely recover on your own in about a week or two. But here’s the kicker: in rare cases, the virus can invade your nervous system.

That’s where things get serious.

Neuroinvasive West Nile: When it becomes dangerous
In less than 1% of cases, WNV can lead to something called neuroinvasive disease—meaning the virus makes its way into your brain or spinal cord. This can cause:

• Encephalitis (inflammation of the brain)
• Meningitis (inflammation of the membranes around your brain and spinal cord)
• Acute flaccid paralysis (a sudden, polio-like paralysis)

The symptoms of severe WNV infection include:

• High fever
• Severe headache
• Neck stiffness
• Disorientation or confusion
• Tremors or seizures
• Muscle weakness
• Coma

If you or someone you know starts showing these signs after mosquito exposure, go to a hospital immediately. Time matters.

Who’s most at risk?
Anyone can get West Nile, but adults over 60, people with weakened immune systems, and those with chronic conditions (like diabetes or kidney disease) are at higher risk for severe symptoms.

But don’t let your age fool you. There have been fatal cases in young, otherwise healthy people too—so no one gets a free pass.

How to protect yourself this mosquito season
Okay, now that we’ve scared you just enough to take this seriously, here’s the good news: prevention works.

Simple steps make a big difference:

• Wear insect repellent with DEET, picaridin, or oil of lemon eucalyptus
• Cover up with long sleeves and pants when outdoors, especially at dawn and dusk
• Dump standing water in birdbaths, plant trays, buckets—mosquitoes love it
• Fix screens on windows and doors to keep the buzzers out
• Stay in air-conditioned spaces when possible
• And no, citronella candles don’t count as mosquito armor.

So the next time you brush off a mosquito bite, pay attention to your body in the days that follow. A mild headache might just be stress… or it could be your early warning sign.

West Nile virus FAQs

What are the first signs of West Nile Virus in humans?
The most common early symptoms include fever, headache, body aches, fatigue, and sometimes a rash. These can appear 2 to 14 days after a mosquito bite. Many people confuse them with the flu or just feeling run-down.

How do you catch West Nile Virus?
You get infected through the bite of a mosquito that has fed on an infected bird. It’s not contagious between people, and you can’t get it through touching or casual contact.

Can West Nile Virus be cured?
There is no specific cure or antiviral treatment for West Nile Virus. Most people recover on their own, but severe cases may require hospitalization for supportive care like IV fluids and pain management.

Who is most at risk for serious complications?
People over age 60, and those with weakened immune systems, cancer, diabetes, or kidney disease, are more likely to develop serious forms like meningitis or encephalitis.

Is there a vaccine for West Nile Virus?
As of now, no vaccine is available for humans—though one exists for horses. Prevention relies on mosquito control and personal protection, like using repellent and avoiding peak mosquito hours.